The movie is subtitled when Elisa has no translator & we need to know what she's saying...

At the point, we see her sign 'trivial' & Zelda translates for Strickland [& the audience]

After they are dismissed, she quickly signs something for which there is neither inworld nor subtitle translation - after he asks her to "Say that again" she signs it slowly & the subs give us one letter at a time..

F ... U ... *... *... ..Y..O..U..

After Strickland asks a second time & Zelda translates as "Thank you" then we are back to accurate translation.

The movie is subtitled when Elisa has no translator and we need to know what she's saying...

At the point, we see her sign 'trivial' and Zelda translates for Strickland [and the audience]

After they are dismissed, she quickly signs something for which there is neither inworld nor subtitle translation - after he asks her to "Say that again" she signs it slowly and the subs give us one letter at a time..

F ... U ... *... *... ..Y..O..U..

After Strickland asks a second time and Zelda translates as "Thank you" then we are back to accurate translation.