Nathan Robitaille has given voice to bloodthirsty vampires and destructive monsters. But with The Shape of Water, the supervising sound editor had to do something entirely different—create a non-verbal language for a creature that, in this case, was not the villain but the romantic lead. It meant giving Guillermo del Toro’s scaly star a kaleidoscope of audible emotions—from sadness and pain to joy and even sexiness. Without dialogue, Robitaille had to invent a way for the creature to not only connect with Sally Hawkins’s character, Elisa—but seduce her.

“This is the first time I’ve been able to give a creature this much range,” Robitaille told Vanity Fair. “We walked away from the first meeting with Guillermo not sure what the creature would sound like [but there was pressure] because he was the romantic lead.”

Rather than recruit trained voice actors to record vocalizations, Robitaille told Nelson Ferreira, the film’s dialogue and A.D.R. supervisor, that he wanted to “take a crack” at voicing the creature himself.

“Honestly, that’s the best way to have endless material if we ever need a vocalization, since you don’t have to worry about bringing an actor back into the studio.”

On set, Robitaille had seen actor Doug Jones, who plays the creature, emit guttural barks from the back of his throat to get himself into character. Robitaille used those dolphin-like noises as initial inspiration.

“I set up my microphone and did a few trial runs, just improv-ing. Once I pinned down the general tone for him, I fleshed out one of the more romantic scenes where Elisa introduces him to music with the record player. I sent that over to [del Toro] and he loved it.”

Robitaille’s vocalization tracks were just the foundation for the creature’s audio—which were layered with inflection elements like “animal sweeteners.” In an early scene, where the creature tentatively approaches Elisa, unsure of whether or not to trust her, Robitaille added a swan hissing to texturize the creature’s uncertainty.

As the creature falls in love with Elisa, Robitaille layered high-resolution recordings of pigeons cooing to score the creature’s more tender moments—like the romantic scene in which Elisa fills up her bathroom with water.

Aside from aurally illustrating the creature’s romantic story arc, Robitaille also accounted for the fact that the creature can only temporarily exist outside of his water tank. “A lot of the sounds that we started layering in were the sounds of his drying-out gills, the liquid gurgling, and the wheezing elements.”