The results of the review were organized by the research questions. First, when counselors or clients speak more than one language, how are languages used during counseling sessions? This question focused on the influence of linguistic elements in counseling sessions including two categories: language selection and language switching. Second, what are the benefits and challenges of counselors and clients participating in multilingual counseling? This question focused on the impact of multilingual counseling on people (counselors and clients) who use the language including two categories: benefits of multilingual counseling and challenge of multilingual counseling.

When counselors or clients speak more than one language, they must first navigate selecting the working language in counseling sessions. This phenomenon did not receive much attention in either multilingual counseling practice or related studies; however, language selection can influence clients’ autonomy and the power dynamic in counseling sessions. Four studies (22.22%) in the current review addressed language selection. Rolland et al., (2017, 2021) investigated multilingual clients’ language selection issues during counseling sessions. They surveyed 109 multilingual participants from 41 different countries and interviewed five multilingual participants about their language practice in psychotherapy. The findings revealed that clients did not always have the opportunity to discuss their multilingualism with their counselors (Rolland et al., 2017, 2021). For some participants, they described it as unnecessary to discuss a language option because of the counselor’s monolingual limitations. Similarly, in a study by Carmen Calvo-Rodríguez (2021), many monolingual psychotherapists in the UK described that language selection is not relevant to counseling, and some of them chose to focus on nonverbal language or use translation devices to facilitate communication.

Although language selection was typically overlooked, a small number of participants in Rolland et al. and’s (2017, 2021) mixed methods study mentioned negotiating language selection in counseling sessions. Researchers discovered that either the counselor or client raised the language selection topic at the beginning of counseling sessions (Rolland et al., 2017, 2021). The results from Rolland et al. (2021) categorized language selection into four scenarios. First, when the counselor and client share more than one language, one language is selected as the dominant working language with some space for switching to the other language(s). Although a shared first language is a natural choice, this is not always the case. Second, the counselor and client can speak different languages or dialects during counseling sessions if they can understand each other. Third, when the counselor does not speak the client’s first language, the counselor confirms whether using another language (generally a local language such as English) is adequate for therapeutic work. Fourth, even though the counselor does not understand the client’s first language, they still open space for the client to switch to that language at times (Rolland et al., 2021).

Language selection can become more complex in family therapy, especially when a language discrepancy exists between the caregivers and children. Vaquero and Williams (2019) interviewed eight psychotherapists who worked with multilingual families in the USA. The results revealed that there are various methods to determine which language(s) can or will be used in therapy sessions. They concluded that psychotherapists need to talk directly with both caregivers and children; they need to choose a specific language based on consideration of not only the dominant language of the caregiver(s) or children, but also the dyadic relationship between the caregiver(s) and children.

When more than one language is used in counseling sessions, it is common for counselors or clients to go back and forth between different languages; this phenomenon is called language switching (Das, 2020; Dewaele & Wei, 2013; Vaquero & Williams, 2019; Verkerk et al., 2021). Language switching can occur either naturally or intentionally (Das, 2020; Rolland et al., 2017); when used with intention, language switching can have therapeutic implications and impact power dynamics in counseling sessions. Eight studies (44.44%) in the current review addressed language switching.

Multilingual counselors and psychotherapists contended that language switching is embedded in their daily lives; in most situations, they are unaware of the process of managing language switching (Das, 2020; Vaquero & Williams, 2019). Multilingual counselors or psychotherapists often attune to their clients’ language usage in emotional expressions based on their intuition rather than professional knowledge (Verkerk et al., 2021). Some multilingual clients reported that they switched their language automatically during counseling sessions (Rolland et al., 2017). Vaquero and Williams (2019) found a similar observation among multilingual families, in which switching language from time to time is a natural flow in the triad of caregivers, children, and counselors during counseling sessions.

Language switching can be used intentionally to serve a variety of functions in counseling sessions (Verkerk et al., 2021) and has meaningful implications for counseling (Kokaliari et al., 2013). Multilingual clients shift from one language to another to (1) recall certain memories, (2) improve social acceptance of certain expressions such as swearing or taboo words, (3) supplement limited vocabulary in one language, (4) find the most correct words or phrases to express feelings, or (5) counter the lack of specific concepts in certain languages, for example, gender categories (Pérez-Rojas et al., 2019; Verkerk et al., 2021). Since emotions are viewed as coded with language (Kokaliari et al., 2013; Verkerk et al., 2021), multilingual clients may switch to their first language because they feel comfortable talking about certain emotional experiences (Carmen Calvo-Rodríguez, 2021; Kokaliari et al., 2013; Pérez-Rojas et al., 2019), or they may choose their second language to distance themselves from certain emotions, especially complex and traumatic ones (Carmen Calvo-Rodríguez, 2021; Das, 2020; Kokaliari et al., 2013; Pérez-Rojas et al., 2019; Verkerk et al., 2021). In family counseling, Spanish–English counselors have observed that Spanish–English caregivers intentionally go back and forth between Spanish and English to serve distinct purposes of communicating with their children (Vaquero & Williams, 2019). Similar to the emotional context of language use, caregivers tended to use Spanish to express warmth and closeness to their children, while they used English to talk about academic disciplines and rules.

In addition to its impact on cognitive or psychological processes, language switching influences power dynamics in counseling sessions. By switching to a language that family member(s) do not understand, one family member can either isolate or shield another family member(s) as well as try to control the counseling sessions (Vaquero & Williams, 2019; Verkerk et al., 2021). Switching to the counselor’s preferred language can help family members accommodate or maintain their distance from counselors (Vaquero & Williams, 2019). Counselors or psychotherapists can choose to speak the preferred language of caregivers or children to empower them from time to time (Verkerk et al., 2021). Multilingual counselors can go back and forth between the caregiver’s preferred language and the child’s preferred language to bridge communication and balance power dynamics in counseling sessions (Das, 2020; Verkerk et al., 2021).

Multilingual counseling can be beneficial to both multilingual clients and counselors, which can be attributed to its cultural and linguistic responsiveness. Multilingual clients can feel empowered by freely using different languages in counseling and counselors, both multilingual or monolingual, can improve their multicultural counseling competence and gain a sense of achievement. Our systematic literature review revealed that empirical evidence to support these benefits is mixed. The discrepancy of findings, particularly among the quantitative articles reviewed, guided us to present the benefits theme by research design.

Five studies (27.78%) in the current review addressed benefits of multilingual counseling using qualitative approaches. Multilingual clients can have a variety of positive experiences of being able to use two or more languages liberally during counseling sessions (Pérez-Rojas et al., 2019). In the study by Pérez-Rojas et al. (2019), bilingual Latinx clients who used Spanish and English in their past counseling experiences reported feeling empowered by having the option of choosing language(s) in counseling sessions, as well as by the counselor’s open-minded and welcoming attitude to clients’ bilingualism. Furthermore, using both Spanish and English enables bilingual Latinx clients to find “the right words in the right language” (Pérez-Rojas et al., 2019, p. 247). In this way, clients can express themselves and their emotions in a more authentic manner, which can facilitate counseling processes, strengthen counselor-client rapport, and improve counseling outcomes. Moreover, multilingual counseling can be especially beneficial for intercultural/multilingual couples, who may experience communication barriers in their daily lives (Tien et al., 2017).

Qualitative studies in the review also offered indication that counselors can also benefit from multilingual counseling. Multilingual counselors obtain a sense of achievement in providing services that meet clients’ needs and improve the accessibility of counseling services (Pope et al., 2022). Moreover, shared language and cultural backgrounds can offer multilingual counselors an opportunity to connect to their clients as well as deepen their understanding of marginalized populations (Trepal et al., 2014). In the study of Carmen Calvo-Rodríguez (2021), monolingual counselors with richer counseling experience reported that working with multilingual clients can enhance their counseling expertise in working with diverse clients. Although they did not understand the meaning, these monolingual counselors provided multilingual clients with the space to speak another language. This helped counselors reflect on whether they were sensitive enough to multilingual clients and improve their expertise in working with clients whose first language was different from theirs (Carmen Calvo-Rodríguez, 2021).

In addition to qualitative approaches, there are two quantitative studies (11.11%) aimed at exploring the benefits of multilingualism in the counseling profession. Based on the Sapir-Whorf Hypothesis (Whorf, 1956) about the interconnecting relationship between language and culture, Ivers and Villalba (2015) conducted a quantitative study examining the effect of bilingualism on counseling students’ self-perceived multicultural counseling knowledge and awareness. They recruited 178 students in a Council for Accreditation of Counseling and Related Educational Programs (CACREP)-accredited master’s program, among which 71 self-reported as bilingual. The researchers used the Multicultural Counseling Competence and Training Survey-Revised (MCCTS-R; Holcomb-McCoy, 2005; Holcomb-McCoy & Day-Vines, 2004) to measure students’ multicultural competence. The results revealed that bilingual counseling students self-reported higher multicultural counseling knowledge and awareness than their monolingual peers, after controlling for ethnicity and multicultural training (Ivers & Villalba, 2015).

Regarding the effect of language switching, Pérez-Rojas and colleagues (2014) conducted an experimental study to examine whether a counselor’s intentional language-switching invitation would positively influence bilingual participants’ perceptions of the therapist. In their study, 63 Spanish–English bilingual university students were invited to watch a 15-min audio-analog counseling session demonstrating work between a bilingual Latina counselor and a bilingual Latina client. In the audio, the client encountered difficulty in expressing herself in English. In the invitation to switch condition, the counselor invited the client to switch to Spanish to express herself. In the no invitation to switch condition, the counselor encouraged the client to try using English to express herself again without a language-switching invitation. After watching the audio, participants were asked to rate the counselor’s credibility and multicultural competence and the bond between the counselor and client. Although the researcher hypothesized the bilingual interaction would be a benefit, the results of this study did not show any significant differences in the participants’ perceptions of the counselor between the two conditions. Lacking long-term immersive conditions and using a student group as the study sample rather than real clients may have led to insignificant results (Pérez-Rojas et al., 2014).

In addition to benefits of multilingual counseling, researchers revealed challenges to clients and counselors as well. Communication blocks and lack of external support create challenges that are represented within the process of counseling, as well as in training and practice environments. Ten studies (55.56%) in the current review addressed challenges of multilingual counseling.

Due to language usage and cultural background discrepancies, both clients and counselors encounter communication challenges in counseling sessions. In dyadic therapy with bilingual Spanish-speaking families, caregivers and children can experience communication breakdowns because their dominant languages differ. For example, caregivers who have limited English proficiency could not understand what children (siblings) discussed in English (Vaquero & Williams, 2019). Although the psychotherapist can work as an interpreter during the session, “the emotional experience gets lost in translation” (Vaquero & Williams, 2019, p. 204). As a result, caregivers and children can only share a limited conversation on simple topics, such as physiological needs (e.g., eating and sleeping); however, when it comes to more complicated topics, such as school life, study, and friendship, caregivers feel an emotional disconnect with their children. Furthermore, miscommunication can easily occur when counselors and clients have different cultural backgrounds, despite shared language(s). This happens when the same word or phrase has different meanings in different cultures (Trepal et al., 2014) or when counselors unconsciously overlook clients’ multicultural backgrounds because of their high proficiency in a shared language (Verkerk et al., 2021).

Lack of proficiency in the shared language also causes communication barriers in counseling sessions, thereby negatively influencing clients and counselors. In Verkerk et al. (2021), a small number of multilingual therapists described their concerns that if clients’ proficiency in a shared language is extremely low, it can be challenging to conduct psychotherapy in that language. Clients may also feel insecure about using less proficient language in counseling sessions (Rolland et al., 2021). Similar feelings of insecurity also occur in counselors who speak the working language with a foreign accent (Pope et al., 2022). Counselor participants in the studies by Johal (2017) and Estrada et al. (2018) reported that the ability to speak a language was not equal to the ability to use that language in counseling. When counselors are less proficient in the shared language with clients, they tend to feel less effective or present in sessions and less adequate to intervene in emotionally intensive topics due to limited emotional vocabulary, thereby interrupting the flow of the therapeutic process (Vaquero & Williams, 2019).

The challenge of low self-efficacy in using a non-dominant language in counseling sessions is also salient in multilingual counseling students. Receiving training only in English, Trepal and colleagues (2014) found that bilingual students who can speak English as well as Arabic or Spanish do not feel confident in counseling Arabic or Spanish-speaking populations. Similar findings can also be found in the study of Alvarado et al. (2019). International students who speak English as a second language reported experiencing difficulties with language barriers, inadequate feelings as a counselor, and self-doubt (Garrison et al., 2022; Georgiadou, 2014).

In addition to the in-session challenges of multilingual counseling, multilingual counselors and counseling students also experience challenges outside the counseling sessions. Some common challenges included difficulty translating documents from English to other languages and vice versa (Johal, 2017; Pope et al., 2022; Trepal et al., 2014), lack of sufficient multilingual counseling training and supervision (Alvarado et al., 2019; Carmen Calvo-Rodríguez, 2021; Estrada et al., 2018; Johal, 2017; Pope et al., 2022; Trepal et al., 2014; Vaquero & Williams, 2019), and lack of resources and necessary support for career development (Alvarado et al., 2019; Garrison et al.,