Korean English classes focus on vocabulary, grammar, and reading. Less obvious differences are present in grammar and vocabulary. They need to know certain vocabulary words, certain structures of grammar, etc. Spanish verbs form one of the more complex areas of Spanish grammar. Sign languages are full-fledged natural languages with their own grammar and lexicon. This is especially noticeable in the grammar of Creole languages. Italian grammar is typical of the grammar of Romance languages in general. Melendez also provided comic interest with his misadventures, poor grammar, and sloppy pronunciation. This includes sentences, words, structure, grammar, and meanings. This is a major influential work on Sanskrit grammar and linguistics. A notable aspect of the grammar of Portuguese is the verb. Verbal communication is a highly structured form of communication with set rules of grammar. It was intended for experts in Biblical Hebrew grammar and morphology. Divergences from the grammar described here occur in some dialects. There were a number of books written on Tamil grammar.