Exact words for exact meaning
To be adept in any particular subject ( art, cuisine or woodwork, for example) you need to know and be able to use effectively its specific language ( especially its vocabulary) which distinguish it from other subjects. Different subjects may use the same grammar, syntax, structure etc. but their vocabularies are subject -specific. Each distinct subject has its own particular and unique words. Many of the words used by a mechanic , for instance, are very different from ,say, those used by a chef.
If you want to be really competent in a subject , it is essential to have skills, of course, but you should know what you are talking about . Your practical skills should be blended with communication skills, of which vocabulary is an essential component.
It is sensible to learn the correct pronunciation of words you use , especially if you are speaking to a group of people, as mis-pronunciations can make you look foolish.