I saw a slogan on an elementary school last week: "We Make Learning Fun!" It grated on me, and not just because it made me feel that I was about to be bombarded with singing cartoon characters.
It was rather the subliminal attitude towards learning it expressed: that learning is naturally a tedious process, but by dint of great creativity on the part of teacher and school, it can be sugarcoated enough to conceal itself as amusement.
Watching D1 tackle the most difficult of life's learning tasks, communication and self-propulsion, I can't say that "fun" is the word that often comes to mind. Certainly I do nothing whatever to make learning to walk and talk "fun." The job is full of frustration, repetition, challenge, pain, concentration, and moments of ecstasy when she at last does something she has been struggling to do for weeks. "Fun" is far too thin of a word for what she is experiencing.
Nor do I need to do anything to press her on to walk and talk. I rejoice with her when she succeeds at something new, but she knows already in herself that she has done something worthwhile. I don't need to hand out rewards to motivate her, or invent games to camouflage what I want her to do. She is learning to walk and talk for two reasons: her own body and mind compel her to try, and she sees people she loves and admires doing these things and wants to imitate them.
Come to think of it, there is quite a bit I could do to destroy the natural interest she takes in this learning. I could try to compel her to practice at times when she is not ready. I could try to hold her back from learning one or propel her forward in another according to what the books say the average child her age should be doing. I could keep her away from adults doing real things so that she had no idea what her end goal was or why she was doing it. I could keep her cooped up so that she never had the chance to stretch her muscles when she felt like it, and bombarded with sounds so she never had the chance to privately practice her own. These would certainly make learning very un-fun. Indeed, if she were not inherently so compelled to learn these things, they might destroy her desire to learn altogether.
What I can do and need to do is simply to provide space, time, example, and every once in a great while the tiniest bit of encouragement or instruction (most of the time these are either confusing or irrelevant). When I do that, there is no need to make learning fun. Learning is a compelling adventure that she is eager to embark on for herself.