'Register' is the term commonly used to describe different levels of formality in language.

“语域”是一个术语，通常用以描述语言中用语的正式程度。

《牛津词典》

Similarly, the formality of register may be identified by its corresponding registers markers (esp. words with different levels of formality).

同样，语域等级也可通过相应的语域标记（特别是不同等级的词汇）得以识别。

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In contrast, in Mexico they tend to register near-identical levels of support, as voters rarely split their ballots.

ECONOMIST: Mexico��s do-nothing legislature