Largo-corto
estrecho-aNcho.
I don't see anybody mixing them up.
I agree, In Spanish it is clear like in the other languages.
French:
long -court
large - étroit
Spanish
largo - corto
ancho - estrecho
Portuguese
comprido - curto
largo - estreito
You can say "longo" in Portuguese, which was probably a better example there.
How do you say "ample" in Spanish then?
Using English in this example is not a true parallel comparison/contrast with the other languages since English does not share the same common ancestor and subsequent development. Albeit, it's useful in letting English speakers know what's going on.
English "long" does not stem from Latin "longus" as the others, although it is cognate with it at the I.E. level. "Long" in English is from Anglo-Saxon "long/lang" < Gmc. *langgaz.
"Large" was borrowed from Norman French < O.Fr., being added to existing words like "great" and "mickle/much" (and later, "big"), and assisting them with restricting still other native words like "stoor" (Modern Dialectal "stoor") in most senses.