What is language detection?

Detection needs a sample before it can decide, and the sample it gets is a greeting response like hello or yes.

Short utterances are genuinely ambiguous. Several languages share words, and one syllable is not much to go on.

Accuracy climbs quickly with more speech, which is why systems often commit after the first full sentence rather than the first word.

Switching mid-call is harder again, and it is common among bilingual speakers who start in one language and settle into another.

Say you run a tire shop in El Paso and a caller opens with "Hola, sí, una pregunta." Your detector has about two seconds of audio. "Hola" is a strong clue, but plenty of English speakers say it as a joke, and "sí" sounds like "see". If the system commits on that alone, it's guessing.

Give it one more sentence, "Necesito cambiar dos llantas", and the guess becomes a safe call. The catch is timing. Your caller has now spoken for six seconds and expects a reply, so the system has to answer in a language before it's fully sure. Wrong guesses cost you more than slow ones here. A Spanish speaker greeted with a fast English paragraph often hangs up, while one who waits an extra second doesn't notice.

You can size the problem before you talk to any vendor. Ask whoever answers your phone to keep a tally for two weeks: one mark for every call that started or ended in a language other than English. Forty marks out of 400 calls is 10 percent of your callers, and that's a requirement. Three marks is an edge case you can cover with a transfer to a bilingual coworker.

Then ask vendors narrow questions. Which languages have they tested on real phone audio, as opposed to clean studio clips? How many seconds of speech does detection need? What will your caller hear while it decides? Can you turn detection off and offer a spoken choice instead, such as "For English, stay on the line. Para español, diga español"?

A vendor who answers with a number of seconds has measured it. If the reply is a flag count, they've read a supplier's brochure.

GreetKeeper is English-first at launch. We are not going to list languages we have not verified on real calls.

That is a limitation worth stating plainly before you buy, particularly if a meaningful share of your callers prefer another language.

Bring a bilingual caller to a demo if this matters to you. A live test settles it faster than a feature list would.