Asking a question or statement

Asking a question or statement
 

The tune Speedy Gonzalez has this line which looks like a question.
Why "decir" and not "preguntar", does not "si" suggest a question?

Y le pudieron decir si con Rosita se casaba

It's a statement.
"And they could tell you/him/her if he was marrying Rosita."

Thank you

On a side note, the line can be presented as a question. No?

In the song, Speedy was awakened after he fainted. And when they could say something to him (le pudieron decir), they asked him a question, but we are hearing a recounting of the event, written as a statement.

Okay so the "they asked" is just understood or implied by the "si"
Is that usual in Spanish to just omit something like that?

The way the lyrics were written seems like a usual way to say that a question was asked.
The verb preguntar could also have been used, but it probably didn't fit the meter of the song.
In either case, no question appears in the sentence. It is a recounting of what was said.

Thank you
Great