To my non-native ear, it sounds awkward to pronounce t and d together. Do you natives agree? Should I use it here?
Can you imagine? It would be hilarious.
Can you imagine? It'd be hilarious.
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What are contractions?
When should you use contractions?
What are some examples of contractions?
There are many incidences of that’d meaning “that would” in the Corpus of Contemporary American English:
SPOKEN 208 (2.39/million words)
FICTION 384 (4.7/million words)
MAGAZINE 58 (0.67/million words)
NEWSPAPER 48 (0.57/million words)
ACADEMIC 3 (0.04/million words)
TOTAL 701 (701/million words)
It is most common in spoken English and fiction, so the idea that it’s more for informal registers has merit.
It is certainly acceptable in the sense that any native speaker would understand it. So, I think that would characterize it as legitimate. In formal writing, most contractions are avoided anyway — though if I were somewhere between formal and informal, I would definitely get rid of that'd before I would get rid of it's. So it is on the "more informal" end of the contraction formality spectrum.