I have been watchin japanese programs and I noticed that people would say dayo. for example ishida uryu dayo onaji class dayo is dayo the casual form of des? i think you use dayo with your friends and not with people that are superior to you. domo arigato

Soufiani-san, Konnichiwa!! You are absolutely correct! DAYO is the combination of DA (shortened/informal version of DESU) and the end particle YO. Taking your example: *Onaji class DAYO* The formal way is to say: *Onaji class DESU*- _"We are in the same class"_ And if you want to add emphasis or assertions, add the end particle YO: *Onaji class DESUYO* - _"We're in the same class!!!!"_

sugoi dayo! domo arigato gozaimashta

Soufiani-san, Konnichiwa! Genki desuka? Just a little Japanese correction: To say "It's great" you wrote: *Sugoi dayo* Well, the correct way is just saying *Sugoi yo *, without the DA. When you want to indicate the idea of "that's why, that's what it is, because of that...". As in, "It IS that it's great" then, you can add the ending *no desu * to *sugoi*: *sugoi no desu*. OR, if you're a guy speaking with friends and family, you can add the ending *-N dayo *instead: *Sugoi-n dayo* It's a bit confusing and tricky because DA is the contracted/informal version of DESU, however, though you can say: *SUGOI DESU*, you can't say *SUGOI DA* Remember, there are two types of adjectives in Japanese: I-adjectives and Na-adjectives. *Sugoi* is an I-adjective because it ends in *I*, well, all I-adjectives follow the same rule, you cannot add *DA* alone. Correct I-adjective phrases: *Sugoi-n da / Sugoi yo *- _It is that it's great / It's great_ *Atsui-n da / Atsui yo* - _It is that it's hot / It's hot_ *Takai-n da / Takai yo*- _It is that it's expensive / It's expensive_ For NA-adjectives, you can just add DA. Here's a list of NA-adjectives with the DA ending. *Kirei da (kireina)* - _It's beautiful!_ *Hen da (hena) *- _It's weird!_ *Taihen da (taihenna)* - _It's tough!_