In my language béu I have the particle TA as a complementizer. That is TA = “that” in the béu equivalent of “he thinks that she will go back to Italy” Now I was thinking of making TA also mean “if” (the marker of the protasis) if the following clause begins with KO (the marker of the apodosis). Both markers are mandatory in a béu conditional sentence by the way. So it would actually be the marker of the apodosis that would trigger the listener to hear a conditional sentence. Is anybody aware of any natlang (or conlang) that does it this way ? And of course if this way of doing things does not exist, then the question is “why not”. Which tendencies in language evolution discourage this pattern from coming about ? By the way, in béu, the verb TAMA (to ask) is a request for information only, not a request for action or a request for an object. (I would also be interested to know, roughly what percentage of natlangs make this semantic distinction).