The most common and most likely answer to this crossword clue is the 8 letter word DIALECTS
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More clues leading to the result DIALECTS
Buddy explains!

The straight part
We know that "Variety in speech" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case variety in speech = dialects.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DIALECTS mean?
DIALECTS noun- A variety of a language that is characteristic of a particular area, community or social group, differing from other varieties of the same language in relatively minor ways as regards grammar, phonology, and lexicon.
- Language that is perceived as substandard or wrong.
- A language existing only in an oral or non-standardized form, especially a language spoken in a developing country or an isolated region.
- A lect (often a regional or minority language) as part of a group or family of languages, especially if they are viewed as a single language, or if contrasted with a standardized idiom that is considered the 'true' form of the language (for example, Cantonese as contrasted with Mandarin Chinese, or Bavarian as contrasted with Standard German).
- A variant of a non-standardized programming language.
- A variant form of the vocalizations of a bird species restricted to a certain area or population.