(1) αδύνατος there's no άδυνατος in Greek. The correct spelling (stress position) is 'αδύνατος'. It both means 'impossible' and 'thin' for a person. It can also mean 'weak' but for skill or knowledge of sth, not in strength. Examples: Αυτό είναι αδύνατο (=this is impossible) Αυτός είναι πολύ αδύνατος (=he is very thin/he's skinny) Είμαι αδύνατος στα μαθηματικά (= I'm not good at maths / I'm weak at maths) I don't know how to leave you a voice response!! :P check out this TTS software though: http://www.oddcast.com/home/demos/tts/tts_example.php?sitepal select Greek and type αδύνατος. The pronunciation you'll hear is correct and natural. (2) γνωστός-διάσημος They both mean 'famous' and they can both be used for people or places, although maybe διάσημος is used for people more often. Actually διάσημος means 'famous', whereas γνωστός means 'known' or 'well-known' Ένας διάσημος / γνωστός ηθοποιός ==> a famous actor Η Σάμος είναι γνωστή για τα κρασιά της ==> Samos is known for its wine

I would like to comment about γνωστός και διάσημος that γνωστός is used for both places and people but διάσημος is used only for people. For example,we say H Ελλάδα είναι γνωστή για τη φιλοξενία της. = Greece is known for her hospitality but we never say "Η Ελλάδα είναι διάσημη για τη φιλοξενία της".= Greece is famous for her hospitality. But we say "O Μάνος είναι έαν διάσημο μοντέλο στην Ελλάδα" = Manos is a famous model in Greece. ή "Ο Μάνος είναι ένα μοντέλο που είναι γνωστό στην Ελλάδα" = Manos is a known model in Greece. Also,synonyms of διάσημος is περίφημος and πασίγνωστος =very well-known.