Half of hearing aids finally interpreting sign language (9)

I believe the answer is:

semiotics

I'm a little stuck... Click here to teach me more about this clue!

'aids finally interpreting sign language' is the definition.
I can't tell whether this definition defines the answer.

'half of hearing' is the wordplay.
'half' becomes 'semi' (I've seen this before).
'of' becomes 'o'.
'hearing' becomes 'tics' (I can't justify this - if you can you should give a lot more credence to this answer).
'semi'+'o'+'tics'='SEMIOTICS'

Can you help me to learn more?

(Another definition for semiotics that I've seen is " Study of signs and symbols".)

I've seen this clue in The Independent.

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