Spanish to English Social Sciences Education / Pedagogy early childhood development

Forgive me for asking two terms at once, but that is part of my dilemma: Do I need two terms in English or will one suffice?

This is a text written by educators specializing in early childhood development. Here's the context:

De 12 a 24 meses. Desde el primer año al segundo año de vida: explorando con autonomía y comunicando con palabras.
Percepción del cuerpo y conciencia motora
Esta es la edad en que se comienzan a llamar **“maternales” y “trotones”**: que caminan y corren. Los niños y niñas continúan su interés por explorar más allá de su espacio inmediato, y sus capacidades de movilidad, junto con su entendimiento de causa y efecto, le llevarán a trepar para alcanzar lo que antes no alcanzaban y a desarrollar estrategias de solución de problemas incipientes. Ahora explora el mundo de manera rápida. Predominan los juegos usando sus músculos gruesos y finos con más agilidad.

I can't find a definition for either term that suits this context, and I don't recall ever hearing a child called by either of these terms. I suspect that the writer actually had an English word (or two) in mind and was attempting to find a (possibly nonexistent) Spanish equivalent. I'm tempted to use just "toddler" to cover both: This is the age when we start to call them "toddlers." But then, what do I do with "que caminan y corren"?

I'm stuck. Any help, suggestions, or information about how these terms are actually used (or more to the point, what English-speaking educators would write in this context) will be much appreciated.

Puerto Rican Spanish to US English, please.