Indo-European language vs Indo-Hittite

Indo-European language and Indo-Hittite both are nouns.

Word	Noun	Adjective	Verb	Adverb
Indo-European language	Yes	No	No	No
Indo-Hittite	Yes	No	No	No

As nouns, Indo-European language and Indo-Hittite are synonyms defined as:

Indo-European language and Indo-Hittite: the family of languages that by 1000 BC were spoken throughout Europe and in parts of southwestern and southern Asia

Other synonyms of Indo-European language include Indo-European.

Indo-European language (noun)	Indo-Hittite (noun)
the family of languages that by 1000 BC were spoken throughout Europe and in parts of southwestern and southern Asia	the family of languages that by 1000 BC were spoken throughout Europe and in parts of southwestern and southern Asia