If you go walking down a street in Spain and we see a little tree, would you say “mira qué arbolito” or “mira qué arbolillo”? Is there any difference?
We have such an interesting variety of the diminutive in spanish, many ways to say that something is little, tiny or sweet. The most common and neutrum forms of the spanish diminutive are -ito and -illo, correspondant with the standard spanish variety. If we use some of the others we will be giving our partner more information about where we come from in Spain, or where we have learnt spanish. This diversity deals with the influence of the native peninsular languages in each different area, don’t forget that we have other four official languages in Spain! For example, the diminutive in catalan is formed with -et/eta and so they form it when they use spanish. And the same happens with galician (-iño/a), vasque (-ico/a) and the rest of the official and non official spanish languages.
However, sometimes the choice can change the meaning of the word, for example plantita means little plant and a plantilla is a template or stencil, and the same happens with gatito, little cat, and gatillo, trigger. Pay attention to those cases!
Apart from the diminutives on the map above we also use, with different geographical references and connotations, -uelo/a, (mozo, mozuelo), -izno/a (lluvia, llovizna), -ajo (miga, migaja), -ejo/a (cosa, coseja), -ujo/a (yerba, yerbuja), -ucho/a (casa, casucha) and many others!