Palatalization is a common phonological process in which a sound develops a palatal articulation. It can be classified into three different types. They are 1) a secondary articulation which attaches itself to a primary articulation; 2) an advanced articulation and 3) a change in the manner of articulation.
Russian is an example of a language with a great deal of palatalization. The word for "thank you" is spasiba, a word with actually has a palatal glide before the high front vowel "i". A more acurate representation of the pronunciation of this word is "spasyiba". Because the high front unrounded vowel "i" is articulated near the palate, it is easy to insert a palatal glide before the vowel. However, another view is that the alveolar fricative is in fact a palatalized alveolar fricative because the fricative has a much longer duration than the glide. In this view the alveolar fricative is analyzed as the primary articulation and the palatal glide as the secondary. If this is the case, the word can be represented as spas'iba. The Russian word for five, "pyat'", is clearly an example of a secondary articulation attached to a primary one. Both the alveolar plosive and the palatal glide occur in the syllable coda, a sound sequence which is common in the Slavic languages but does not occur in many other languages such as English, German, Spanish and French.
An example of an advanced articulation occurs in the word "key". If we compare this word to the word "car", it is clear that the voiceless velar plosives in each word are not identical. In the word "key", the velar plosive has a more advanced articulation than it does in the word "car". The reason for the advanced articulation of the velar plosive in the word "key" is due to the articulation of the vowel. It is a front vowel which results in a more palatal articulation of the velar plosive. This can be viewed as a type of assimilation because the velar plosive becomes more similar to the vowel which follows it. Since the vowel influences the preceding segment, the direction of the assimilation is regressive.
With the words "car" and "key", one may ask how we know that the velar plosive of "key" is in fact an advanced articulation and that the velar plosive of "car" is not a retracted articulation. In isolation, the velar plosive does not have an advanced articulation. Other evidence comes from the word "cheese". This word used to be pronounced "keese" [kiz] but the velar plosive became an alveopalatal affricate. In German this word is Ka:se, in Dutch it is "kaas", in Spanish it is "queso" and in Portuguese it is "queijo". It becomes clear that only in English did the velar plosive become an affricate and it is plausible to speculate that it developed an advanced articulation prior to affrication.
Another common type of palatalization is in the change of articulation. In the word "nature" the "t" is pronounced as a voiceless alveopalatal affricate. However, this was not always the case. In French "nature" and German "Natur" the "t" is pronounced as a plosive. This was almost certainly also the pronunciation of the word "nature" at an earlier stage of English. The schwa in the second syllable of "nature" is classified phonetically as a central vowel, but the high articulation often triggers palatalization. This is also the case in words such as "creature", "feature" and "capture".
In English, a number of words may or may not have palatalization depending on the speaker. In most of England, palatalization applies in the words "tube", "new" and "duty". The first segment in each of these words is pronounced with the blade of the tongue, sounds which are known as coronals. In most of the United States, the words "tube", "new" and "duty" are pronounced without palatalization, a process which is often referred to as yod-dropping. For those speakers who do not palatalize, "do" and "dew" sound the same, but for those who do, they are distinct. In the case of words which start with the voiceless alveolar fricative such as "suit" and "sue", most British speakers do not palatalize but a few do.
The phonological process of palatalization is very common in the languages of the world. In the case of the Slavic languages, it is especially common. Palatalization can be viewed as a subclass of assimilation and can be further classified into three types, the attachment of a secondary articulation to a primary one, a more advanced palatal articulation, and a change in the manner of articulation of a particular segment.