I think that there is a small difference. Klar means do you understand it, in the way that military/police radio users would say "copy that". Deutlich is more like, is that well/clearly written, is it easy for most people to understand.
So my German is Klar (someone can understand it) but is not deutllch (not well formed).
I have the same question, I wonder if they are always interchangeable. Looked it up on dict.cc and they seem quite similar, although they may have different two-word constructs, e.g.: "deutlich sichtbar" (conspicuous), "nicht eindeutig" (ambiguous). I guess familiarity with the language will help with knowing when to use one or the other...
Yes, but for intermediate learners this is low prority, unless you are planning to take a dictation exam.
"-ig" is much softer than a "-ich". If you know the difference between "-chen" and "-ich" then "-ig" is like the former. It is difficult to write the difference, but try to make the sound of a bike tyre puncture that's an "-ig", try to make the sound a tyre inflating machine makes when you pull it from the tyre, thats an "-ich" a quicker and harder sound.
BTW many Germans don't speak with a Hochdeutsch accent and one very common variant is just to say "-isch" for both, so some will say "Fisch", "Zwanzisch" (20) and "isch" (ich) with more or less the same ending.
"Die Frage ist deutlich" doesn't sound quite right to me, although I am not a German "Muttersprachler" "Deutlich" means distinct or unambiguous, whereas here the sense is of there being a situation where a choice has to be made. Gibt's eine(n) Muttersprachler/in die/der alles erklaeren kann?
They are nearly completely different in meaning. In fact they don't have any overlap, but the English word "distinct" can mean different things as well.
"deutlich" means "precise", "clear" or "manifest". You can sometimes translate it by "distinct" in the sense of "clearly uttered, so that one can understand it well" or as in "there is a clear distinction between these two".
"individuell" means "individual" or "single". You can sometines translate it by "distinct" in the sense of "everybody has his own / a different one".
Langenscheidt's New College German Dictionary gives, as a perfectly acceptable synonym for "deutlich," the adjective "intelligible." I used it and was marked wrong by DL.. How can DL simply fly in the face of solid and respected sources--especially when there's absolutely no context to guide the practitioner--and decide that a legitimate answer's "incorrect." That's so bogus.
I did--8 months ago--and it still hasn't been remediated. And, FYI, my "preferred dictionary" Langenscheidt) isn't the only lexical source that cites "intelligible" as a valid synonym for "deutlich." Bantam; Biolingus, TU Chemnitz; Collins; Duden; Leolingo;, and Linguee.de--inter al.--also give it .the stamp of approval.