Are you interested in trying out the Best Grammar Apps? While it depends on the use case but if you are looking for a Do it yourself app that can help you in parts of speech identification, we would certainly say you should try the nounshoun - free grammar app. Nounshoun is an Artificial Intelligence - english grammar app that can find Noun, Verb, Preposition etc. in any sentence. Noun, Verb, Prepositions etc. are called Parts of speech and form an integral part of English grammar.