[alach11]

I can't comment on Japanese, but broken Spanish can be confusing (to me) due to verb conjugations. Conjugations are also a major sticking point for new learners of the language since they have a big impact on meaning but can be hard to remember.

For example, changing a single letter in "quiero" ("I want") can have a big impact on its meaning by becoming "quiere" ("He/she wants") and "quieres" ("you want").

See this page for the 142 possible conjugations of the verb querer: http://www.spanishdict.com/conjugate/querer