When words fail, the brain can find ways to speak through music

Authors: Lieke A. Heijmans is an undergraduate student at the Linguistics program of the University of Groningen, The Netherlands. Adrià Rofes is associate professor in Neurolinguistics at the University of Groningen, The Netherlands.

Losing the ability to speak doesn’t always mean losing the ability to communicate. For many people living with aphasia (i.e., a language disorder typically caused by brain damage), this scenario is not science fiction. At any given moment, people with aphasia may struggle to speak, find words, or form sentences. And yet, they can still blurt out well-worn phrases like “I don’t know”, utter curse words, or sing familiar songs without hesitation.

Why does this happen?

The answer lies in the brain’s backup system for language and speech. Music and what scientists call “formulaic language” reveal the brain’s hidden pathways and offer hope for communication when traditional speech is lost. An example of how this hope can be put into action is Melodic Intonation Therapy – a technique that uses melody and rhythm to help people speak again ¹.

What is behind this backup system?

Brain regions in the periphery of the Sylvian fissure, like the very famous Broca’s and Wernicke’s cortical areas, are thought to be critical for propositional language, that is, the type of language that has to do with constructing new and meaningful sentences with the goal of expressing original thoughts ². In other words, most of what we consider propositional language has to do with producing and comprehending sentences such as “I saw a bird in the garden this morning” or “Let’s meet at the café after work.”.

But not all language is novel or propositional. Think about how often we say phrases like “Thank you”, “Oh no!”, or when we sing “Happy Birthday”. These are examples of formulaic language. That is, the type of language that is fixed and that contains overlearned language bits that we use over and over again, often without thinking. These chunks of language are thought to be stored as whole units in long-term memory, relying on cortical structures of the left hemisphere, such as those mentioned for propositional language, as well as areas in the right hemisphere and subcortical structures like the basal ganglia ³. Interestingly, formulaic expressions account for approximately one-third to one-half of our daily speech, depending on the context (Van Lancker Sidtis & Sidtis, 2018; Győrfi, 2017). Formulaic expressions are fast, automatic, and deeply tied to rhythm, emotion, and communicative-pragmatic context – key ingredients for how the brain remembers things.

The dichotomy between propositional and formulaic language has led researchers to propose a dual-process model of language ⁴. According to this theory, the brain uses two separate systems to process language. Roughly speaking, one system is located in the left hemisphere and used for generating novel, grammatical speech, and another system is located in the right hemisphere and subcortical areas (like the basal ganglia) and used for retrieving automatic speech, including songs.

Formulaic expressions play a key role in social and emotional interactions. They help us connect, show politeness, and express urgency or empathy. These expressions are emotionally charged and context-bound, which may explain why they are stored in the right hemisphere – a hemisphere that, in turn, is known for handling emotions and social context ⁵. Interestingly, people with damage to the right hemisphere or subcortical areas may exhibit fluent language but have a reduced ability to use emotional or formulaic speech ⁶ . Individuals with right hemisphere damage may indeed sound “empty or robotic”. In other words, their language lacks the spontaneity of everyday conversation.

In this sense, formulaic language acts like a “back door” to language and speech. These expressions bypass the brain’s semantic system, which is responsible for understanding word meanings and selecting the right word in context. When we produce propositional speech, the brain selects the right words, accesses their meanings, and builds the sentence. But formulaic expressions may disregard some of these processes. To be more precise, they do not necessarily require semantic or syntactic planning; they can be retrieved as sound patterns and rely on motor memory (how to move your mouth to say the phrase) ⁷. In short, you do not need to “mean” a formulaic phrase to say it the same way you “mean” a propositional phrase. In a way, you just need to remember how the phrase sounds.

Singing survives

The difference between formulaic and prosodic language also explains why singing often survives in people with aphasia. Producing familiar songs stimulates sensorimotor (movement-related) brain areas and shifts language processing to the right hemisphere. Familiar lyrics are stored as sound templates in long-term memory. Hence, they can be recalled automatically, without the need for semantic or grammatical processing. Importantly, the connection between music and language can be exploited to help people with aphasia to regain their language skills, for example, through the development of Melodic Intonation Therapy. This type of therapy uses melody, rhythm, and tapping (e.g., on a table) to help patients speak again. The idea behind Melodic Intonation Therapy is quite straightforward: by engaging the musical right hemisphere, we can reroute language functions around damaged left hemisphere areas, as a sort of compensation (Govathi Nikhila, 2018).

Reports of preserved singing in aphasia go back over 250 years. Wilson et al. (2006) reported the case “KL” – a man with severe language impairments (i.e., global aphasia) after a left hemisphere stroke. KL could not form new sentences, but he could sing familiar songs fluently. In their study, KL practiced 30 phrases. For some of the sentences, he trained using Melodic Intonation Therapy, for other sentences he was asked to use repetition alone, and then for another series of sentences he received no training at all. The results? Phrases practiced with Melodic Intonation Therapy were retained longer and spoken more accurately than the other two sentences. This finding supports the idea that singing creates unique memory representations that can bypass damaged language systems, offering a separate pathway for language access.

But the story is even more intriguing! Early brain-behavior theories argued that music activated the right hemisphere to take over language and speech duties. However, newer research using brain scans reveals something even more fascinating: Melodic Intonation Therapy reactivates left hemisphere areas, such as Broca’s area, suggesting that melody and rhythm can help the brain “rewire” itself – a process known as neuroplasticity (Wilson et al., 2006). Now, to say a bit more, while Melodic Intonation Therapy does not fully restore propositional speech, it does improve the ability to produce memorized phrases more effectively (Wilson et al., 2006). And that matters! Regaining formulaic phrases can help patients reconnect with loved ones, express basic needs, and reclaim a sense of identity. Formulaic sentences are there to boost motivation, well-being, and quality of life ⁸.

In short, when the brain’s ability to build sentences collapses, it may not mean the end of communication. Thanks to music and formulaic expressions, people with aphasia can find a way back to language and communication. These automatic phrases and familiar songs can be produced by bypassing damaged areas – revealing the brain’s hidden pathways for language and speech. Melodic Intonation Therapy has this potential, using rhythm and melody to reroute language function and foster recovery. Indeed, sometimes, all that is left is a phrase, a curse word, or a song, and that may be enough to reopen the door to language.