Principles of Arabic Grammar Part I is a free Android application developed by IGY that provides a complete encyclopedia of Arabic grammar. The application serves as a reference point for learning the basics of Arabic grammar in an easy and interactive way. The app is designed to help users learn the fundamentals of the language, including the definition of grammar, sentence structure, parts of speech, and verb and noun conjugation.

The app is divided into four parts, and each part covers various topics. Part I includes the definition of grammar, sentence structure, parts of speech, and verb conjugation. Part II includes noun declension, interrogative nouns, comparative nouns, conditional nouns, verbal nouns, attached nouns, and plural nouns. Part III includes a discussion of defective verbs, abstract and augmented verbs, incomplete verbs, passive verbs, and the five verbs. Part IV includes discussions on the subject, the object, the predicate, the verb "to be" and its derivatives, the conjunctions, the exceptions, the adverb, the apposition, the state, the distinction, the attribute, and the emphasis.

Overall, Principles of Arabic Grammar Part I is an excellent resource for anyone who wants to learn Arabic grammar. The app is easy to use and provides comprehensive information on the basics of Arabic grammar.