The Day of the Dolphin (1973) on Netflix

Zoologist and behavioral psychologist Dr. Jake Terrell and his team, which includes his wife, Maggie Anderson Terrell, are funded by the Franklin Foundation to conduct research with dolphins, namely to learn why they do the things they do. Their primary subject is a dolphin named Alpha - Pha for short - who was born at their research facility four years ago, and who the team raised after Pha's mother died. What Harold DeMilo, Jake's primary liaison at the Foundation, is unaware of, as is the rest of the world, but what Jake eventually divulges to DeMilo when he threatens to pull funding, is that Jake and Maggie's primary work is teaching Pha how to communicate in English. DeMilo vows to keep this information confidential as the Terrells are afraid of the outside world trying to exploit Pha. This work has stalled of late, with Pha refusing to speak, they believe because he has reached his sexual maturity. As such, they introduce a female dolphin named Beta, or Bea for short, to the research. It does more than the trick as Pha not only begins to communicate in English again, but also teaches Bea. Much to Jake's chagrin, DeMilo sends an "old friend" named Curtis Mahoney to the facility for a tour. What Jake and the team is unaware of is that Mahoney, who is not an old friend, blackmailed DeMilo to gain access. The team learns from DeMilo that Mahoney, out of that tour, is aware of the research and is threatening to go public. The Terrells figure they have to take preemptive action. However, what is happening with Mahoney is not all it appears on the surface, and involves a plot, indeed exploiting the dolphins, for a much more nefarious reason. When the Terrells learn what is happening, they not only try to foil the plot, but also have to make the difficult decision of what to do with Pha and Bea, which in turn may risk their research.