Mamá, Papá

Mark at Language Log links to a cartoon that deals with the universality of the sounds in the words mother and father, and their origin, that includes an interesting punch line:

It's so amazing: "ma", "pa" are some of the first and easiest language-like sounds babbling babies make - and what's the word for "mother in English? "Mama"! And it's also "mama" in Dutch, and in Romanian, and in Catalan, Slovak, Quechua, Chinese, German, Russian, and MORE.

My contribution to the topic at hand will be relating it to Romance, certainly; this time, in particular, to Spanish.

In Spanish, the standard word for mother is madre (from Latin MATREM). Mamá would be the equivalent, in usage, to the English mom; and mami would then be mommy. Amá and ma are also heard, depending on region and sociolect, though they are considered non-standard.

The paradigm for father is very similar: padre is father (from PATREM); papá, dad (equivalent, again, in usage); papi, daddy; and, non-standard apá and pa (the first one of this pair, as above, often stigmatized).

The Language Log post referenced spurred an interesting discussion, regarding the first sounds a baby can produce, comparing and expanding the issue with regards to other languages, and how all of these words are common, as it seems, to the majority the world's languages.
Some of the related words discussed there include breast, grandma and milk. Building on this, at least in Mexico, and perhaps Central America, a slang word for breast is chichi; teta is a standard word for nipple, and is often used colloquially with the meaning of breast, and also baby bottle.
The standard word for grandfather is abuelo (often in its diminutive form, abuelito, to show endearment), and in some places, tata may be used instead; in other places, tata is actually used as an affectionnate term for father. Connected to the Spanish tata, it must be pointed that the standard word for father in Romanian is tată, coming from the Latin TATA (dad). The Lewis & Short dictionary on Perseus compares the Latin word to the Greek τέττα (tetta), and the Sanskrit tātas.
Abuela is then Spanish for grandmother (like its masculine counterpart above, often abuelita; or, colloquially, especially among young people, shortened to ábue). The feminine analog to tata would be nana, the origin of which is listed as voz infantil (children's voice) on the RAE. Nana is also the word used for nanny in some countries, often interchangeable with niñera (from niño, child).