#vaguely!

Sure, it might be coincidental, since there's not much cause for the hobbits to encounter Gondorian civilians. But the soldiers who do it don't seem super important in the book, especially the "many" soldiers in Minas Tirith who talk behind Pippin's back in Sindarin.

And then there's someone like Ioreth, a civilian known by what's likely a Sindarin nickname (Ioreth means "old woman"). She doesn't seem to be fluent in Sindarin and is unfamiliar with Sindarin terms for familiar plants. But she sometimes uses Sindarin terms where Westron ones are also in usage (like perian instead of "halfling"). So it's probably not the case that all Gondorians can be divided into 100% fluent in Sindarin (or Quenya) and 0% fluent.

But we do hear that a) Gondorian warriors are expected to have skills beyond military ones + b) military skills are now particularly prized in Gondorian society, above all others. It does make a certain Tolkienian sense that the other skills Gondorian soldiers are expected to have would include singing in Sindarin and Quenya, honestly, and that this would also be a marker of the relatively high status conferred on them in contemporary Gondorian culture.