A sentence is defined as any utterance with a complete meaning, whether it is formed by one or more words, or whether it has verbs or not. For this reason, we can say that "Wonder has developed into a mature, versatile artist." It is a set of words that has complete meaning, so it is a sentence.
Sentences are intended to express ideas, emotions, orders, appeals, etc. Intonation is responsible for clearly indicating the beginning and end of a sentence, as well as helping to make sense of it.
