Here's something fascinating about human language: no matter what language you speak, a small set of high-frequency words accounts for most of what you say every day. This isn't just an English-language finding. It holds across Spanish, Tagalog, Mandarin, Arabic, and every other language that researchers have studied.
For AAC users and their families, this has real implications. Especially for the millions of bilingual and multilingual families who need their child's AAC system to work in more than one language.
The Core Vocabulary Principle Is Universal
The basic idea behind core vocabulary is straightforward. In any language, a relatively small group of high-frequency words makes up the vast majority of everyday communication. These words are used constantly across every topic, every setting, and every age group.
What makes this remarkable is how consistent the pattern is across languages. The specific words change, of course. But the structure stays the same. Every language has a small core of high-frequency, flexible words that do the heavy lifting, surrounded by a much larger set of lower-frequency, content-specific words.
Baker, Hill, and Devylder (2000) demonstrated that core vocabulary use remains consistent across different environments and communication contexts. A child uses similar core words at home, at school, and at the playground. This finding, while originally studied in English, reflects a property of language itself, not a quirk of any single language.
How Core Words Map Across Languages
Let's look at some examples. The following are not exact translations, because languages don't map one-to-one. But they illustrate how the same communicative functions appear in core vocabulary across languages.
"Want"
| Language | Core word | Notes |
|---|---|---|
| English | want | |
| Spanish | quiero | First person, from "querer" |
| Tagalog | gusto | Also means "like" in many contexts |
| Mandarin | 要 (yào) | Also covers "need" and "will" |
"More"
| Language | Core word | Notes |
|---|---|---|
| English | more | |
| Spanish | más | |
| Tagalog | pa | Short, very high frequency |
| Mandarin | 还要 (hái yào) | Literally "still want" |
"Go"
| Language | Core word | Notes |
|---|---|---|
| English | go | |
| Spanish | ir / vamos | "Vamos" (let's go) is extremely common |
| Tagalog | punta | Often used as "punta tayo" (let's go) |
| Mandarin | 去 (qù) |
"No" / "Not"
| Language | Core word | Notes |
|---|---|---|
| English | no, not | |
| Spanish | no | Same word for both functions |
| Tagalog | hindi | Negation marker |
| Mandarin | 不 (bù) / 没 (méi) | Two negation words with different uses |
The pattern is clear. Every language needs ways to express wanting, requesting more, indicating movement, and negating. The core functions of communication are human universals. The specific words are just how each language packages those functions.
What About Fringe Vocabulary?
While core vocabulary is strikingly similar across languages, fringe vocabulary is where the differences become much more interesting.
Fringe words are the content-specific vocabulary: names of foods, animals, places, cultural practices, and everyday objects. These words are deeply tied to culture and daily life.
Consider food vocabulary. A Tagalog-speaking family might need words like "sinigang," "adobo," and "kanin" (rice, as a meal staple). A Spanish-speaking family might prioritize "arroz," "frijoles," and "tortilla." An English-speaking family in the American Midwest might need "casserole" and "mac and cheese." None of these words would appear on another family's high-priority fringe list.
The same goes for:
- Family terms. Many languages have far more specific kinship vocabulary than English. Tagalog distinguishes between "kuya" (older brother) and "ate" (older sister). Mandarin has different words for paternal and maternal grandparents.
- Cultural and religious vocabulary. Holiday names, prayer words, ceremony-specific language.
- Environmental vocabulary. Words for local animals, weather patterns, geography, and plants vary enormously by region.
This is why fringe vocabulary can't be a one-size-fits-all list. It needs to reflect the child's actual world. And for bilingual families, that world spans more than one language.
What This Means for Bilingual AAC Users
If your family speaks more than one language at home, you're not alone. Bilingualism and multilingualism are the global norm, not the exception. And for AAC users in bilingual families, language representation on the device matters.
We have a detailed guide on AAC and bilingualism, but here are the key points as they relate to core vocabulary across languages.
Core words should be available in the home language(s)
Because core vocabulary is structurally similar across languages, setting up a bilingual AAC system is more achievable than it might seem. The same small set of functions (wanting, going, negating, describing, requesting help) needs to be represented. The words just need to be in the right language for the right context.
For many bilingual families, this means having core vocabulary available in both languages. A child who speaks Tagalog at home and English at school needs "gusto" and "want," "pa" and "more," "hindi" and "no."
The home language is not optional
There is sometimes pressure, either from professionals or from the system itself, to default to English-only AAC. This is a mistake. Research consistently shows that bilingual children benefit from maintaining both languages. Restricting a child to one language on their AAC device means cutting them off from full participation in their home and family life.
A child who can only say "I want water" at school but can't say the equivalent to their lola (grandmother) at home is not being fully supported.
Code-switching is normal and healthy
Bilingual speakers naturally switch between languages within a conversation. This is called code-switching, and it is a sign of linguistic competence, not confusion. A bilingual AAC user might say "I want" in English at school and then switch to Tagalog when talking to a parent at pickup.
An AAC system should support this, not fight it. Ideally, the device makes it easy to move between languages without losing access to core vocabulary in either one.
Practical Considerations for Multilingual AAC
How should languages be organized on the device?
There are a few approaches, and the best one depends on the child, the family, and the AAC app:
-
Separate language pages. Each language has its own home page and vocabulary set. The child switches between them. This is the simplest to set up but can be slower for code-switching.
-
Bilingual core with language-specific fringe. Core words are available in both languages from the main page. Fringe vocabulary is organized by language in separate folders. This mirrors how many bilingual speakers actually use language.
-
Unified layout with translations. Each button shows the word in both languages (sometimes with the primary language on top and the secondary below). This can work well for families who mix languages freely.
There is no single "correct" setup. The right answer is whatever supports the child's actual communication patterns.
Who decides which languages to include?
This should always start with the family. Parents know which languages are spoken at home, which relatives speak which language, and which language the child hears most. The SLP or AAC specialist can then help figure out the technical implementation.
One important note: even if a therapist doesn't speak the family's home language, that doesn't mean the home language should be left off the device. Families can help with vocabulary selection, pronunciation, and modeling in their language. The therapist's role is to support the AAC system and language development strategies. The family's role is to bring the language itself.
What about languages with different scripts?
Languages like Mandarin, Arabic, Hindi, and Korean use writing systems that differ from the Latin alphabet. For AAC users who are pre-literate or emergent readers, this is less of an issue because the device relies primarily on symbols and pictures rather than text. But for users who are beginning to read, having the correct script on the device reinforces literacy in both languages.
Many AAC apps handle this through symbol-based communication, where the picture stays the same and only the label text changes between languages. The symbol for "eat" might show the same image whether the label reads "eat," "comer," or "kumain."
The Research Landscape: What We Know and What We Don't
It's important to be honest about the current state of research. Most AAC vocabulary studies have been conducted in English, with English-speaking participants, in English-speaking countries. The foundational research on core vocabulary, including the widely cited finding that a few hundred core words account for the vast majority of daily communication, comes primarily from English-language studies.
That said, frequency-based vocabulary research in other languages supports the same general pattern. Linguists studying Spanish, Mandarin, Arabic, and other major languages consistently find that a small set of high-frequency words dominates everyday communication. The 80/20 pattern is not unique to English.
What we have less of is AAC-specific research in non-English languages. We need more studies on:
- How bilingual AAC users actually navigate between languages on their devices
- Which core words should be prioritized in specific languages for AAC beginners
- How cultural differences affect vocabulary selection and organization
- The outcomes of bilingual vs. monolingual AAC interventions for bilingual children
The field is moving in the right direction. More researchers are studying AAC in multilingual contexts. But for now, clinicians and families often need to adapt English-based guidelines to their own language and culture, using the universal principles of core vocabulary as a starting point.
Core Vocabulary as Common Ground
One of the most encouraging things about the core vocabulary research is that it gives us common ground across languages. If you understand the principle that a small set of high-frequency, flexible words powers most communication, you can apply that principle in any language.
For a bilingual family setting up AAC, this means:
- Start with core words in the child's dominant or home language. The same categories matter everywhere: wanting, going, having, being, negating, describing.
- Add the equivalent core words in the second language as the child encounters that language (at school, with certain family members, in the community).
- Build fringe vocabulary around the child's actual life, which will naturally reflect their cultural and linguistic environment.
- Don't force a single language. Communication is the goal. If the child communicates best by mixing languages, support that.
For a deeper look at which core words to start with, check out our core words list for AAC. While the list is in English, the categories and priorities translate well across languages.
Choosing an AAC App That Supports Multiple Languages
When selecting an AAC app for a bilingual family, consider these questions:
- Does the app support your languages? Not all AAC apps offer multilingual support. Check whether your home language is available before committing.
- How easy is it to switch between languages? If switching requires navigating through menus, the child may avoid it. Look for apps that make language switching quick and accessible.
- Can you customize vocabulary in each language? You'll need to add culturally relevant fringe words. Make sure the app allows you to edit and add vocabulary in all relevant languages.
- Does the app use symbols or text, or both? Symbol-based systems can work across languages more easily than text-only systems.
For more guidance, see our full guide on choosing the right AAC app.
The Bottom Line
Core vocabulary is one of the closest things we have to a linguistic universal. The same principle, that a small set of flexible, high-frequency words powers most communication, holds across every language studied. For AAC users and their families, this is good news. It means the foundational strategies for building communication work regardless of what language you speak.
For bilingual and multilingual families, the message is clear. Your child's AAC system should reflect the languages they actually live in. Core vocabulary gives you a framework that works across those languages. And your child's home language is not a barrier to AAC success. It is a bridge.
SabiKo is a free AAC app designed with Filipino families in mind, supporting communication across languages and cultures. Download it on Google Play and start building your child's vocabulary today.