It's pronounced "tav" and is often used in the same way as the English "good."
Here are some examples of how it's used:
* טַב דְּבָרָא (tav d'vara) - "a good word"
* טַב עִבְרִית (tav ivrit) - "good Hebrew"
* טַב יוֹמָא (tav yoma) - "a good day"
Note that Aramaic, like many languages, has regional variations. This is the most common form of the word.