Postby Pollyanna » July 10th, 2009 7:45 pm
Kartoushka is more casual word: Pachom eta kartochka? - "How much does this potato cost?" (in a market)
Kartofel is less casual, it is used in news, textbooks, articles etc: Kartofel' papulyaren v padsobnyh hazyaistvah - Potato is popular in personal subsidiary plots. (in Internet news)
Chips/French Fries are an exception. I have never heard "Frie Kartoushka", but "Kartofel' frie" is definitely correct. I always say "Kartofel' frie" and people around as well.