Yeh-yuh (noun): a sound somewhere in between the pronunciation of each of his sisters' names. May mean one sister, or both, or any kindly larger girl-character who smothers him in kisses and falsetto. Officially, Yeh-yuh receives the distinction of having been his first uttered word.
Mama (noun): mostly means mother. Sometimes means father. Occasionally means teacher or other attentive larger-than-a-Yeh-yuh creature.
Dada (noun): mostly means father. Sometimes means mother. Ditto: larger than a Yeh-yuh.
Uh! (verb, command): Lift him. Now. We didn't catch on to this immediately because (forgive us) it sounds a little like the non-verbal jabber he bubbles all day. Three strikes on us. Uh! the first is an utterance. Uh! the second is a sterner utterance, accompanied by the classic the-field-goal-is-good referee maneuver. Uh! the third is a sharp crack with goal with bouncing bottom, immediately followed by tears. We have displeased His Majesty with our slow response and ineptitude.
Bah-buh (interjection): goodbye. Also means hello, how are you?, what's up, dude? Sporadically accompanied by a hand wave or outstretched palm, which is itself a demand for some high-fiving. Bah-buh may be offered in greeting or in farewell; it is just as likely used to command the attention of a stranger who has not yet admired his adorableness. All subjects must admire adorableness.
Dah! (interjection), also alternately Gah! or Flah! May mean: I am dissatisfied; I have an opinion; you're not noticing me; I want to participate in the conversation. Often accompanied by table banging. When it is accompanied by food flinging, prepare yourself to minister to his disappointment rapidly.
Travel safely, and remember the customs of the land. Bah-buh.