A good example recently from current events was the US president being asked in a press conference to commit to a peaceful transfer of power, "win, lose, or draw". He responded with "we'll have to see what happens". In the context of the question being posed, that's a clear and explicit failure to commit, given that context.

Context can entirely invert the meaning of two identical statements, and, in the right context, a failure to do a certain thing, or even remaining silent, can indeed be an explicit statement.

Another case comes from 2013, Salinas v Texas, when the police were questioning a murder suspect who suddenly became quiet during questioning when the topic turned to the murder. They were able to use this sudden silence as incriminating circumstantial evidence, given that specific context. This resulted in silence in the face of questioning by the government having to be explicitly invoked as such to not be potentially incriminating, which is an odd state of affairs and probably not the best outcome, but you can however tell that those judges weren't completely insane. Silence after saying "I affirmatively invoke my right to remain silent" is very different than silence after you were just answering police questions voluntarily, until they asked you about a murder they thought you committed.

Silence can speak volumes, explicitly, given the circumstances preceding and surrounding that silence.

Desmond Tutu, winner of the Nobel Peace Prize, once said:

“If you are neutral in situations of injustice, you have chosen the side of the oppressor. If an elephant has its foot on the tail of a mouse, and you say that you are neutral, the mouse will not appreciate your neutrality.”