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By: Alison On: August 17, 2016 In: Interpreting, Translation Comments: 5
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Language proficiency levels aren’t always easy to define. Translators, interpreters and linguists define different levels of language proficiency with different terms: bilingual, fluent, proficient, native speaker and others.

But the terms used to define language proficiency are not strict and are often used loosely or interchangeably. Since the use of vague terminology can lead to confusion or misrepresentation of just how skilled an individual really is in a language, it’s important for professional translators and interpreters to have working definitions for the various levels of language proficiency.

Just how can we define these terms, and when is it appropriate to use each of them? Here are some of the most commonly-used language proficiency labels and when they should or should not be applied:

Native Speaker

The term native speaker is equal to that of “mother tongue,” and it is generally safe to use these two terms interchangeably.

A native speaker’s language is his first language. This usually means that it dominated his youth and is therefore the language he does his thinking in. A native speaker is more than fluent — he correctly and easily uses his first language.


Like a native speaker, a fluent speaker of a language is very comfortable with the language — however, it is not necessarily his first, native or mother tongue. Although it’s difficult to achieve, fluency can be attained through extended study and, usually, with time spent living in full linguistic immersion.

Merriam-Webster defines the adjective “fluent” in reference to language as “capable of using a language easily and accurately.” It’s important to note that while a fluent speaker may be nearly perfect, he may require more conscious concentration when speaking and may not have the same spontaneity as a native speaker when it comes to idioms and similar terms and phrases.


Turning back to the dictionary, “proficient” is defined as “well advanced in an occupation, art, or branch of knowledge.”

In terms of language, the “proficient” label can therefore be seen as referring to a speaker who, while very skilled in the use of a language, uses the language with greater formality and less familiarity than a native or fluent speaker.

Bilingual, Trilingual, etc.

These words are some of the most misused among language proficiency terminology! Someone may say they are trilingual when in fact they perhaps speak one language as a native speaker, a second language fluently and the third at only a proficient level.

The dictionary definition of “bilingual” is “using or able to use two languages with equal fluency.” Unless each language gets spoken with equal strength, the term “bilingual” could be misleading.

Why Language Proficiency Needs to Be Defined

It might seem nit-picky to differentiate between various terms relating to linguistic proficiency, especially since the differences can be trifling. In fact, it’s the relative similarity of these terms that makes the need for more concrete definitions all the more necessary, in order to avoid confusion and misrepresentation of an individual’s linguistic capabilities.

It should be noted that, while the descriptions above aim to clarify these terms, they are by no means concrete, go-to definitions. In an ideal world, those in the language professions would develop and use an official industry standard of language proficiency terms in order to more accurately represent their capabilities as interpreters and translators.

Until such a standard is adopted, however, those requiring language services should seek to verify a linguist’s language proficiency.

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    • Olga Davido
    • November 03, 2016
    • Reply

    Thanks you very much. I ruse and malay.

    • Emily
    • September 09, 2017
    • Reply

    I came across this article, and I just had to point out that someone’s first language may not be his/her most natural or fluent language. Many people who’ve immigrated at a young age speak their first language with much less fluency than the language of their schooling (and the language of their friends), They express themselves much more naturally, with a much better vocabulary usage, in the language of their environment. Many struggle to master their parents’ language, which is often also their own first language. They cannot understand idiomatic expressions, misuse words, and cannot communicate effectively without inserting their other language. And if their parents did not make an effort to use their first language at home, some of them even go as far as to lose their first language entirely and cannot even hold a basic conversation in it. For this reason, I find it problematic to define a native speaker’s language is his/her first language. When you cannot communicate fluently in this language, would you still consider this their native tongue?

      • Dakota Bennett
      • September 13, 2017
      • Reply

      Good point, in this case, I would probably not consider their parents language their mother tongue anymore… I’d think whatever language you do most of your natural, spontaneous thinking in would be your native language, and even though they started learning one first, the second one, for example someone who moves from Poland to the United States at a young age, would have English become their native tongue versus Polish. But that’s completely opinion based, and you make a very good point that I’d be interested in seeing someone answer with more clarity or perhaps actual researched insight into it. (I find it interesting that I just happened to come across this article as well that actually has a very recent comment to reply too.)

    • Mel
    • December 11, 2017
    • Reply

    Even when moving to another country at a later age (let’s say 20) there is still the possibility to become a native speaker in the language of the new environment and often become less confident in the mother tongue (if you don’t use it much). You think and speak like a native speaks when fully emersed into another language for a while. The hardest bit to get rid of is the accent, but even that can be aquired at a later age when being fully emersed in the language and culture for several years and with the right mindset.

    On average, studies have shown, that if you haven’t started speaking a language on a daily basis (ideally in a country where ot is spoken) from the at of 15. After that age it gets harder and harder to reach a level that is indistinguishable from the language of a native speaker. However, with the right attitude and the right environmental factors (e.g. not speaking the native tongue much and being fully immersed in the second language), this level can be achieved at any point in life.

    I consider myself as fluent speaker though I have no doubt that I will be accent free and on a native speaker level in a few years. I have been learning English at school since I was 10, but only aquired fluency at the age of roughly 22, when I spend 6 months in New Zealand. However, one year later I moved here and now I have been living here for 2 years.

    If you speak like a native speaker, then you should be considered just that.

    • Everson
    • December 14, 2017
    • Reply

    A lot of kids in the Philippines are growing up as “monolingual ESL speakers”. They are not taught Tagalog or their regional language. They are raised and surrounded by adults who speak English as second/ foreign language, with all its limitations in vocabulary, levels of expression (like the lack of phrasal verbs etc). It produces pathetic results.

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