There are three kinds of shevas: video
- A vocal sheva which looks like a colon : and is preceded by a long vowel (or is under the first letter of the word); see here.
- A silent sheva which also looks like a colon but is preceded by a short vowel ; see here.
- A composite sheva which is a sheva joined with one of the other vowels; see here.
- Gutturals will not take a vocal sheva; it will shift to a composite sheva. Gutturals will take a silent sheva.
- Letters with a sheva for the vowel will often lose their dagesh (assuming they had one); see the Coal Mine letters.
- “A silent sheva is usually placed in a final kaf in order to distinguish the latter from a final nun, e.g. הָלַךְ.” Van der Merwe, A Biblical Hebrew Reference Grammar, 38.
- When two shevas occur on the beginning of a word, changes occur; see here.