A letter with a short vowel is mutaḥarrik (vowelled); one without a short vowel is sākin (vowelless). A letter bearing tashdīd is mushaddad (doubled).
In رَبَّ, the bāʾ is doubled: in pronunciation, the first occurrence is vowelless and the second is vowelled.
The doubled dāl in مَدَّ differs from an undoubled consonant. Tashdīd can therefore be crucial to a word's morphological structure and meaning.
Opening interactive controls...
Vowelled, vowelless and doubled letters
Introduction to ʿIlm al-Ṣarf and Basic Terminology
A letter with a short vowel is mutaḥarrik (vowelled); one without a short vowel is sākin (vowelless). A letter bearing tashdīd is mushaddad (doubled).
In رَبَّ, the bāʾ is doubled: in pronunciation, the first occurrence is vowelless and the second is vowelled.
The doubled dāl in مَدَّ differs from an undoubled consonant. Tashdīd can therefore be crucial to a word's morphological structure and meaning.