Standing comes before talking. You're right that since he can stand, he is, in English-speaking terms, a toddler. I have no idea if Japanese makes that distinction. But a toddler can usually stand and walk months before first words, and expressing complete thoughts can be a year away still at that point.That's clearly not a baby, That's a toddler at the earliest, he should be talking at this point, yet he's still acting like a baby.
Probably the artists fault.