“Means” is a noun, synonymous with “way”.
Remembering the noun phrase “a means to an end” is a good way to revise the way to use “means”. You are correct to say “the language was a means to (learn the thing they want to learn)” and it is basically saying you used the language to get to the goal. You may want to be a bit more specific about what the goal is as it will make your delivery clearer, e.g. “the English language was the means for her to truly understand Shakespeare”. Here are some examples of it in use:
“The train was the only means they had to get there”.
“He ran every day as a means to getting a six-pack”.
Also it might be interesting to know Immanuel Kant’s philosphical theory of morality states that people should be treated as “ends themselves” rather than as a means to an end. This means that “using” people to get what one wants (e.g. just being nice to get money) is immoral and people should be treated as the target of an action to develop a moral society. Hope it helps!