In phonetics, palatalization (ˌpælətəlaɪˈzeɪʃən, also US-lᵻˈzeɪʃən) or palatization is a way of pronouncing a consonant in which part of the tongue is moved close to the hard palate. Consonants pronounced this way are said to be palatalized and are transcribed in the International Phonetic Alphabet by affixing the letter ⟨j⟩ to the base consonant. Palatalization cannot minimally distinguish words in most dialects of English, but it may do so in languages such as Russian, Japanese, Norwegian (dialects), Võro, and Irish.
In technical terms, palatalization refers to the secondary articulation of consonants by which the body of the tongue is raised toward the hard palate and the alveolar ridge during the articulation of the consonant. Such consonants are phonetically palatalized. "Pure" palatalization is a modification to the articulation of a consonant, where the middle of the tongue is raised, and nothing else. It may produce a laminal articulation of otherwise apical consonants such as /t/ and /s/.
Phonetically palatalized consonants may vary in their exact realization. Some languages add semivowels before or after the palatalized consonant (onglides or offglides). In such cases, the vowel (especially a non-front vowel) following a palatalized consonant typically has a palatal onglide. In Russian, both plain and palatalized consonant phonemes are found in words like большой bɐljˈʂoj, царь tsarj and Катя ˈkatjə. In Hupa, on the other hand, the palatalization is heard as both an onglide and an offglide. In some cases, the realization of palatalization may change without any corresponding phonemic change. For example, according to Thurneysen, palatalized consonants at the end of a syllable in Old Irish had a corresponding onglide (reflected as in the spelling), which was no longer present in Middle Irish (based on explicit testimony of grammarians of the time).
In a few languages, including Skolt Sami and many of the Central Chadic languages, palatalization is a suprasegmental feature that affects the pronunciation of an entire syllable, and it may cause certain vowels to be pronounced more front and consonants to be slightly palatalized.