Using proper intonation when speaking English contributes a great deal to overall intelligibility.Originally Posted by nurul
It can get rather involved. It's not always simple, but there are typical and usual intonation patterns which are used without any thought given to using them. English language learners oftentimes require explicit instruction in this area if they are to learn it.
There is also "tone". To me, "tone" is: a deviation from typical or usual intonation patterns in order to add emphasis or alter meaning in some way.
This sort of added or extra stress on certain words also contributes to overall intelligibility. Using "tone", which I would consider to be a paralinguistic feature of language, helps us to express ourselves more clearly. However, it's not something we think about.
Adding extra stress to words or syllables unintentionally can, at times, contribute to misunderstandings, as intonation/tone can indicate something about the speaker's attitude or disposition.
Intonation and tone require practice on the part of language learners, and teachers should be able to model appropriate intonation patterns for students. It's my understanding that intonation gets very little attention, if any at all, in many ESL/EFL classes. It's also my experience that instruction in proper intonation is vital to intelligibilty in some cases. I would include stressing vowels properly as using proper intonation. There is the matter of pronouncing vowel sounds correctly, but that's another topic. It is very much related, however.