By: Alison On: April 15, 2020 In: Interpreting, Translation Comments: 12
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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 their first language. This usually means that it dominated their youth and is therefore the language they do their thinking in (though there are some exceptions). A native speaker is more than fluent — they correctly and easily use their first language.


Like a native speaker, a fluent speaker of a language is very comfortable with the language — however, it is not necessarily their 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, they 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. If you’re considering translation or interpreting services, make sure you think carefully about exactly what you require of your language provider. Although freelance translators and interpreters may be a more appealing choice at first glance, language service companies often save you time and money and provide certified translations you can trust.

How Accredited Language Can Help

At Accredited Language, we offer certified translations in 250 languages and dialects and have more than 35 of experience in the industry. We take the time to carefully vet each of our linguists. All of our translators and interpreters are trusted not only for their linguistic ability, but also for their expertise in subject specific vocabulary. This ensures more accurate translations and interpretations you can depend on.

If you require language assistance, contact us today.

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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.)

        • Jesse Potts
        • June 20, 2018
        • Reply

        Hi, I’m actually in this exact situation. My first language was Spanish because my mother is from Spain but English dominated my childhood and while I would say I’m pretty good with Spanish, English is my best language by far. For this reason I still say Spanish was my first language but English is my mother-tongue/native language.

    • 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.

    • Kathy
    • April 14, 2018
    • Reply

    I find this an interesting subject -a friend of our son who migrated at a very young age from India speaks perfect english and aside from a slight southern twang due to where she was raised, has no discernable Indian accent. I am assuming she does not recall her native language well and I’m assuing her parents are not too proficient in English, but what was so very odd to me was when they showed up at a school event, my son’s friend spoke in English to her parents with a very heavy Indian accent. It was astounding to us and I’m sure we looked bewildered because it almost came across as making fun of being of Indian heritage….she obviously wasn’t, but why would she speak English with an Indian accent? Why not just speak English with no accent as she does with her friends or speak Hindi as best she could? It was just a really odd moment.

      • Anja
      • June 12, 2018
      • Reply

      Hello Kathy,

      I have friends who speak to their parents with an accent too but in my example they are of Southeast Asian origin. Their parents have spoken to them in English with an accent since childhood, because they have learned English at a later age and did not grow up using it. So the children know how to speak with an accent but they also know the “proper” way of speaking through movies, the media and educational institutions. I think it’s just like people who speak in a regional dialect at home but use the proper way of speaking in school and work and with outsiders in general. And most of my friends, just like in your example, would not try to speak in their native language with their parents, because they did not really grow up speaking it at home. The parents may have used it but often the children use English to answer back and are not fluent.

    • Jose Rodriguez
    • May 29, 2018
    • Reply

    Well, I have another case: my two sons, born out of parents from Latin America (thus in principle with Spanish as mother tongue), have lived abroad due to my job, most of their lives…….. thus attending English-speaking Schools, and their level of English is pretty much that of a native……… Their level of Spanish is lower, especially written. A few years back, as we moved to a French-speaking country, they also learned French at the school, plus interacted in French on the street, etc. Thus, their level of French is just as high, and perhaps higher than Spanish……. while English remains their strongest language (quasi Native). It is difficult for them to explain that English, not their mother tongue, is the main language, with French/Spanish following……….. but I am sure that there are many other similar cases, with other combination of languages………..

    • Unknown
    • May 27, 2019
    • Reply

    What if this person first language is Vietnamese, but that person didn’t grow up in Vietnam and never got the chance to learn it fluently so that person can only speak it, but not so well. This person grew up in America so that person can speak, read and write in English well. This person Spanish classes in the past so that person also knows a bit of Spanish. This person also knows a little bit of Korean, but very very little. What would this person be?
    This is probably confusing so I’ll put the order of which languages they can speak the best at.
    1.) English – can read, write, speak really well
    2.) Vietnamese – knows enough to survive in Vietnam, cannot read or write, can speak Vietnamese, but not too good
    3.) Spanish – knows colors, numbers, other objects, cannot read, write or speak correctly
    4.) Korean – self taught so horrible at it, most likely will get lost in streets in Korea, knows the alphabet letters and a couple of words

    • Lavinia Novais
    • August 23, 2019
    • Reply

    I’ve been having quite a hard time and kind of lost. I live at my native country and use daily my native language, but still, I’m forgetting it. Although basic day to day chatting is speakable-aside from many blanks-, my essays and formal vocabulary is just vanishing (even if I’m a avid reader and college prep student).

    • Israel
    • February 08, 2020
    • Reply

    A native speaker is more than fluent — they correctly and easily use their first language – the author is kidding, right? Native speakers commit more grammatical lapses than a fluent speaker.

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