diminutive (or pet name) of a given name is a short and/or affectionate form. diminutive (or pet name) of a given name is a short and/or affectionate form. 

The most common diminutives (at least among English names) are those that are short forms of the original name, very often from the first syllable or sound of the name. 

Diminutives can also be formed by adding a suffix to the original name or the name's short form. 

Diminutive suffixgroup of letters that are added to the end of a word to show that something is smaller than things of that type usually are, for example 'ling' added to 'duck' to make 'duckling'.


Here are some common suffixes used to create diminutives in English.

-y or –ie (Sally, Maggie, Bobby, Jimmy, sweetie, hottie)
-sie, -sies or -sy (sissy from sis or sister, popsy from pop, another word for dad), tootsie,halfsies from halfitsy-bitsy - this is its own word meaning very small)
-o or -io (bucko (from buck another word for a guy), daddio (from dad), kiddo (from kid),Jacko)
-s (Wills, Becks, Bells)


More diminutive suffixes: 


LanguageLearningBase.com (short: llb.re) is an online community for learning foreign languages.
It represents an open knowledge base. Every member can share and gain knowledge about a new language.