Register and style

As we´re studying language, we saw in class some items of how we use it in every situation, they are register, tone and style.
Register:  is a variety of a language used for a particular purpose or in a particular social setting. For example, when speaking in a formal setting, an English speaker may be more likely to adhere more closely to prescribed grammar, pronounce words ending in -ing with a velar nasal instead of an alveolar nasal (e.g. "walking", not "walkin'"), choose more formal words (e.g.father vs. dad, child vs. kid, etc.), and refrain from using contractions such as ain't, than when speaking in an informal setting.
Tone: is the use of pitch in language to distinguish lexical or grammatical meaning—that is, to distinguish or inflect words. All verbal languages use pitch to express emotional and other paralinguistic information, and to convey emphasis, contrast, and other features.
Style:  is a set of linguistic variants with specific social meanings. In this context, social meanings can include group membership, personal attributes, or beliefs.