The Spanish word 'mamita' comes from adding the diminutive suffix '-ita' to 'mamá', meaning 'mother'. The word 'mamá' itself derives from Latin 'mamma', which was a child's word for 'mother' or 'breast'. This type of word is considered part of 'nursery language' - simple words that babies and young children naturally tend to make when learning to speak.

The diminutive '-ita' makes 'mamita' an affectionate way to say 'little mother' or 'dear mother', similar to saying 'mommy' in English.

The most obvious related Spanish words are 'mamá' and 'mama', both meaning 'mother' or 'mom'. These are among the first words Spanish-speaking children learn, just as 'mama' is often one of the first words English-speaking children say.

English speakers will recognize the similarity to words like 'mama', 'mom', and 'mammary'. All of these come from the same ancient baby-talk root that gave us the Latin 'mamma'. It's interesting to note that similar-sounding words for 'mother' appear in many languages around the world, as the 'm' sound is often one of the first sounds babies can make.