The Ho-Chunk language (Hoocąk, Hocąk), also known as Winnebago, is the language of the Ho-Chunk people of the Ho-Chunk Nation of Wisconsin and Winnebago Tribe of Nebraska. The language is part of the Siouan language family and is closely related to other Chiwere Siouan dialects, including those of the Iowa, Missouria, and Otoe.

"Winnebago", a name now used for the Ho-Chunk who were forcibly removed to Nebraska, is an exonym, an Anglicization of the Sauk and Fox word Oinepegi. The anglicized form of the endonym is "Ho-Chunk".

Ho-Chunk's vowel sounds are distinguished by nasality and length. That is to say, the use of a nasal vowel or a long vowel affects a word's meaning. This is evident in examples such as pąą /pãː/ 'bag' compared to paa /paː/ 'nose', and waruc /waˈɾutʃ/ 'to eat' compared to waaruc /waːˈɾutʃ/ 'table'. All of Ho-Chunk's vowels show a length distinction, but only /i a u/ have nasal counterparts.

Ho-Chunk's consonants are listed in the following table:

Typical of Mississippi Valley Siouan languages, Ho-Chunk has aspirated /p/ and /k/ phonemes but no aspirated /t/.

In Ho-Chunk, vowels /i a u/ always occur as nasalized when they follow nasal consonants /m n/. Nasality spreads to an adjacent vowel if that vowel is nasalizable as well. Nasality spreads across syllable or word boundaries and can move across consonants /h/ and /w/, but is blocked by all other consonants. Examples include nąįžą /nãĩʒã/ 'a tree' and ha'ųwį /haʔũwĩ/ 'we (exclusive) do':

nąą

tree