True. The majority of nouns in Hebrew do not experience vowel changes when suffixes are added to them. Nouns in Hebrew are typically organized into patterns or templates that determine how they behave when suffixes are attached. These patterns are designed to maintain the root form of the noun's vowels. While there are exceptions, and some nouns may undergo vowel changes, the general rule is that most nouns remain relatively consistent in their vowel patterns when suffixes are added.