English verbs can't be inflected as strongly as in many languages. But as in many other areas, English makes up for this in many ways. The imperfect tense can be expressed in English; it just can't be expressed simply, by conjugating a verb.
As I understand it (as a rudimentary Spanish speaker), in Spanish, the imperfect tense indicates that the action of a verb took place, and was completed, before the present. So:
Yo caminaba
means that, at some unspecified point in time, I walked, repeatedly or for a long time, but that I don't necessarily do that type of walking any more.
Sometimes, in English, we express this meaning using the simple past tense, and the meaning is made clear by context. For example:
You were trapped in the library for eight weeks? How did you pass the time?
I read.
In Spanish, I'm guessing this would be expressed in the past imperfect. In English, the imperfective aspect of the verb--that it happened repeatedly or over a period of time--is not expressed in the verb, but it is clear from the context.
Sometimes, the imperfective nature of the action is expressed by the use of a phrase associated with the noun. So:
I ate raisins constantly.
is understood as an action taken repeatedly and completed in the past, because of the use of the adverb of time "constantly." Most of the examples of the Spanish imperfect I found also used a similar term--"a menudo," "cada dia". In English, combining one of these words with the past tense expresses the imperfect.
It's surprising how much can be expressed by context. I'm currently studying Chinese, which doesn't inflect its verbs at all and has no conventional tenses or moods at all. "You shi" can can mean "I am, "I was," or "I will be." When you ask a Chinese speaker how he or she can tell whether it's a statement about the past or future, the Chinese speaker will tell you: if I say "yesterday" it's the past, and if I say "tomorrow," it's the future. The same is, to a lesser extent, true for English. In most cases. even without the verb inflection, you can tell from context whether we're talking about the imperfect or the simple past.
Best Answer
This article suggests that originally the expression was: "parler français comme un Basque espagnol".
It can't be correct or not since it's a proverb. Proverbs may not be very grammatical.
I'm not aware about direct proverb counterpart in English, so I would suggest translating it by its meaning:
"To speak broken English" — incorrect or awkwardly structured English, usually spoken or written by non-native speakers (Urban Dictionary)
TL;DR: The problem with translating proverbs is need to convey the context. Historically, people are only aware about neighboring nations, and, of course, there are jokes about each other. An average English (or American) reader or listener may not be simply aware what's wrong with Spanish cows (or Spanish Basques). It has changed in a recent centuries, but still not sufficient to understand tiny details of a humorous context.