That's amusing, considering that you made two rather bad errors in the above comment ("If you can't be assed" and "language and written communication is unimportant"). Granted, a Hacker News comment is hardly the same thing as a CV, but I still detect a touch of hypocrisy here. What makes you so sure that your own GitHub READMEs are free of errors? People have a tendency to gloss over their own mistakes.
As for "language and written communication is unimportant", the full statement was: "It's not like language and written communication is unimportant...". That seems correct to me.
Technically, it should be "It's not as if language and written communication are unimportant."
If we were to nitpick style, we'd say that the double negative is unnecessary, and that "It's..." construction is flabby. So we'd reduce the sentence further to "Language and written communication are important." Debatably, even this statement is reducible to "Written communication is important." From there, we could even cut down to "Communication is important," assuming that "written" is redundant in context.
Not trying to be cute; just illustrating a point. You could argue that I'm reducing too far and slicing away some nuance. Nevertheless, a primary goal in writing is to make a point as succinctly as possible. This is doubly true in short-form writing, such as in resumes and cover letters.
I don't see the errors there. "If you can't be assed to do X" seems standard English to me, if informal. What would you say is wrong with that?
"Language and written communication is unimportant" seems arguably OK to me. Both are mass nouns / uncountable, so the "is" there seems quite defensible to me (v.s. "are", which I assume is your contention?).
