chau, nihongo jouzu ja nai.
chau=chigaimasu with Osakaben dialect. means 'no it isn't']
nihongo = japanese language
jouzu = good or skilled.
ja nai = not]
so it's: [No it isn't, (my) japanese isn't very good.]
Osakaben (kansai dialect) is cool sounding...it's like the 'New York City' version of Japanese. alot of things are abbreviated, structure and grammer rules are broken and much slang is added. Japanese of other regions regard it as rough sounding and too direct. Most of Japan's best comedians have an Osakaben accent.
This is the area I lived and studied most of my limited Japanese. also had a couple semesters before that at Berlitz in Boston.
A Tokyo dialect is pretty much considered standard...although people in Osaka think Tokyo dialect sounds too feminine for men. A telling sign of a Tokyo accent is at the end of a sentence, many times they add 'yo'. 'yo' meaning 'you know.'
so take my sentence and lets make it with a Tokyo accent:
"chigaimasu yo, nihongo jouzu ja arimasen yo."
sounds softer with less abrupt endings in pauses. Thats the main difference between Osaka-Tokyo accents. hard vs soft. like NYC vs LA accents.