Please help me clear my confusion regarding the following sentences and correct me if i am wrong.
My proficiency level(s) of both the english language and the French language (are/is) about the same. Second question, can i only use language once at the back. For example, English and French language.
I am equally proficient in both the english and French language(s).
The verb refers back to the proficiency levels, not the languages, so how many proficiency levels do you have? One, or two?
You could refer to your language skills as one thing no matter how many languages you can speak - but as you are making a comparison, it must be between two things. You are not comparing the languages, but your ability to speak them, so you should use 'levels' and 'are':
My proficiency levels of both the English language and the French language are the same.
You could also group the two languages together this way:
My proficiency levels of both the English and French languages are the same.
This has no bearing on the choice of verb "is" or "are" as this refers back to the 'proficiency levels' not the languages.
Your second option is also a comparison as you are saying two things are equal, so you must use the plural languages.
I am equally proficient in both the English and French language(s).
You could use "My proficiency levels in both the English language and the French language are about the same." You could shorten it to "My proficiency levels in both the English and the French languages are about the same, and you could shorten it further to "I am equally proficient in both the English and French languages."
All three sound a little awkward. Usually "English" is used as the name of the language, so "I am equally proficient in both English and French" would often be better. If you are referring to proficiency in speech then "I am equally fluent in English and French" would be more natural.
Note that I have changed "levels of" to "levels in", and I have left out the word "both" as unnecessary on my last example.
