If I wanted to translate "To fill a cup" and "To fill up a cup", are there in Latin 2 different words to translate "fill" and "fill up"?
To fill up = to fill totally.
If I wanted to translate "To fill a cup" and "To fill up a cup", are there in Latin 2 different words to translate "fill" and "fill up"?
To fill up = to fill totally.
Grammatically speaking, there is a parallelism between Engl. {fill/fill up} and Lat. {plere/complere}, respectively. Typically, English particles and Latin prefixes can express similar meanings. In this case, we are dealing with so-called completive-intensive particle and prefix, respectively, which profile the resultant state and make it especially salient. It is important to point out that their similarity is due to the fact that these two languages belong to the set of so-called "satellite-framed languages" (for general remarks on the classification of Latin within this typological set, please see my answer to a previous question on Latin prefixes. For some useful references on this topic, please see my answer to the question on Latin as a satellite-framed language).
As for frequency of usage, there is an important difference to be pointed out with regard to the particular case you're interested in. English speakers seem to use the verb fill as frequently as fill up, whereas this is not the case in Latin since the prefixed verbs (complere, implere, etc.) are by far much more frequent than its non-prefixed variant (plere).