"He did not say it to me."
Translation:Ní dúirt sé é liom.
"Ní dúirt sé é liom" sounds really awkward to me. And yeah, Irish has gotten enough corruption through English, we should be trying to curtail that rather than encourage it. Gaeilge lofa líofa, as we call it. I find this course useful mainly for strengthening vocabulary and for practice. Other than that, you'd learn way faster from a good grammar book.
I agree that unmotivated changes to the caighdeán should be avoided but in my opinion vitality is more important than canonicity - if a community communicates in Irish that should be celebrated, even if they say 'like' or 'just' every couple of sentences. Is fearr Gaeilge briste mar a déarfá.