T-style

In a formal setting with an unknown papālagi visitor, a Samoan would be expected to use the formal t'''-style, but Ali’imalemanu started his performance in k-style and then switched over to t'''-style after a few minutes. Later on when he knew me better he mixed the two styles when he told me stories (and, of course, always used the k-style when we talked together with no recorder on, no matter what the subject was).

Source: wiktionary

The diachronic development of the oral-based k--style concurrent with the literary-based t'''-style has resulted in their unique co-existence in the twentieth century, and has given rise to clearly defined domains of usage for each style.

Source: wiktionary

The two styles are in a diglossic relationship to one another, with the t'''-style used to mark respect and formality in contexts such as preaching, prayer and radio broadcasts, and in conjunction with use of “chiefly language”, while the colloquial k-style is used in more intimate and/or informal contexts such as the home, when joking, and in casual conversation. The t'''-style is the one usually taught to foreigners, but the majority of younger New Zealand-born Samoans do not have full mastery of this style or of chiefly language, with the result that they have a tendency to hang back from talk with older interlocutors in contexts where use of these more formal styles is expected (Hunkin 2003).

Source: wiktionary