Hebrew Diacritics - Geresh

Geresh is a mark, <׳> that may be used as a diacritic, as a punctuation mark for initialisms, or as a marker of Hebrew numerals. It is also used in cantillation.

As a diacritic, the geresh is combined with the following consonants:

letter value with
geresh
value usage
ג ג׳ slang and loanwords
(phonologically native
sounds)
ז ז׳
צ צ׳
ו ו׳
ד ד׳ For transliteration of
sounds in foreign
languages (non-native
sounds, i.e. sounds
foreign to Hebrew
phonology).
ח ח׳
ס ס׳
ע ע׳
ר ר׳
ת ת׳

Read more about this topic:  Hebrew Diacritics