Both can be translated by “language” which is confusing. French language differenciates both :
"Langage" is the ability to communicate (general concept). It’s also the system (spoken or written) you use to express yourself. This system can be made of technical vocabulary, specific grammar rules, jargon, slang… : it really is the general “concept" of communicating. We can differenciate two “langages" when both don’t use the same rules/codes.
- Il faut apprendre le langage commercial pour devenir un bon vendeur : One must learn the commercial speech to become a good seller. > The specific jargon of business/sellers = commercial language
- Mon fils et moi n’utilisons pas le même langage, il utilise le vocabulaire de la rue alors que je parle un français soutenu comme dans les livres : My son and I don’t use the same language, he uses street vocabulary while I speak formal French like in the books = The son uses a language which codes are different from his mother’s, so they don’t use the same language.
- On utilise le langage HTML pour créer une page internet : We use HTML to create an online page. = we use a language made of codes which structure is different from the language we use to express our thoughts or emotions for example.
- Les enfants font l’apprentissage du langage vers 2 ans = Kids learn how to communicate verbally around 2. = The children learn by themselves how basic codes can work together to make themselves understood.
A “langue” is a group of languages which all have a special feature in common. It has its own codes. For example : the “general language” using Latin roots, using conjugaison in three groups, which pronouns are je-tu-il-elle-on-nous-vous-ils-elles, is French language > La langue française. The “Langue française” is the name of the set of many different jargons that all use these said codes : slang and formal speech (aka the mother and son example), commercial speech… all technical/slang languages that use the same grammar and synthax.
- Le français est la langue maternelle de cet enfant : French is this kid’s mother tongue. : This kid speaks French since forever, he’s been taught different languages of a same “langue” since his first words. For example, a kid will first learn the language of emotions, like “I’m hungry, I’m thirsty, I’m sick, it hurts, I’m happy”, then he’ll learn the language of facts : “this fork is dirty, it’s sunny” etc… but it all is included in one single mother tongue.
- Elle étudie une langue latine, l’espagnol, ainsi qu’une langue germanique, l’allemand. : She studies a latin language, Spanish, as well as a germanic language, German. : She studies different languages that use different grammar and synthax codes and that can be labelled as Spanish and German.
Comparison between “Langue” & “Language”.
In few cases, the frontier between both is quite blurry. Let’s take the example of Sign Language.
We can labelled this practice after two names : Langage des Signes or Langue des Signes.
Le Langage des Signes is the ability to communicate with hand gestures. You can sign either words, letters, or numbers, which could all be common to other languages. For example, if I sign H-E-L-L-O (letter by letter), I’d sign the same word than written “Hello” or spoken “Hello”. It’s the exact same word using the same each letter=one sign system. It’s sort of “English sign language” : English language spoken with hand gestures.
La Langue des Signes is the language that uses hand gestures to transcript its own grammar & synthax. If I want to say “hello”, I’d sign this :
You no longer have letters to sign, it’s a word on its own, a word that is made and understood from all people using Sign Language, whether they are English, French…