First language
A first language is the language a person acquired first in childhood and usually understands most deeply, sometimes called a mother tongue or native language. For communication and consent it is the safest target: people follow health, legal and safety information most reliably in their first language, even when they have some English.
How it works
A person's first language is the one they acquired earliest and typically process most easily, especially under stress or with complex information. Someone can function in a second language day to day and still understand a consent form, a diagnosis or a legal notice far more reliably in their first.
That gap is why communication and consent are safest in the first language. Assuming that some English is enough is a common and consequential mistake.
How SourceTarget uses it
For consent and high-stakes information, SourceTarget targets the reader's first language rather than assuming English will do, because reliable comprehension, not mere familiarity, is what these documents require.
First language compared with Second language
| First language | Second language | |
|---|---|---|
| Acquired | Earliest, in childhood | Later, after the first |
| Comprehension | Deepest, most reliable under stress | Can be partial, especially for complex content |
| Safest for | Consent, health and legal information | Everyday, lower-stakes communication |