日本語を話せます (nihongo wo hanasemasu) means "I can speak Japanese". You can also say 日本語が分かります (nihongo ga wakarimasu), which means "I understand Japanese".
nihongo wo hanasemasen 日本語を話せません。First off, learn to spell Japanese correctly, BONZI I believe "I don't speak Japanese" is Nihongo wo hanashimasen. "I can't speak Japanese" is...