Crossword Genius

Not suitable for use by quick talkers? (4,8)

Ross

I believe the answer is:

dead language

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This might be a double definition.

'not suitable for' is the first definition.
The definition suggests a singular noun which matches the answer.

'use by quick talkers?' is the second definition.
The definition suggests a singular noun which matches the answer.

Can you help me to learn more?

(Other definitions for dead language that I've seen before include "Latin, for example" , "Grave accent a help, maybe" .)

I've seen this clue in The Globe and Mail.
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