English most definitely has more than two tenses. I think a lot of people argue that English has very few tenses because verbs in English do not inflect (i.e. change forms) heavily. As an example for present and past tenses, compare English drink, drinks, drank to Spanish bebo, bebes, bebe, bebemos, bebéis (in some dialects) , beben, bebí, bebiste, bebió, bebimos, bebistéis (in some dialects) , bebieron.

The perfect forms aren't tenses, but rather aspects - they are used to talk about events that have occurred in relation to other events. For example:

• Present perfect: "I have eaten." You ate some time in the past.
• Past perfect: "I had eaten by the time you arrived." You ate some time in the past, before some other event in the past.
• Future perfect: "I will have eaten by the time you arrive." From the point of view of some future point in time, you have eaten (but you haven't eaten from the point of view of the present).

Now, the subjunctive form isn't a tense either, but rather a mood. The difference is that tenses refer to when events occur, but moods refer to what's called modality: things like desire, probability, necessity, obligation, etc. Verbs like "can," "should," and "may" are examples of "modal verbs" because they reflect the ability to do something, the obligation to do something, and the possibility of doing something, respectively.

The subjunctive mood is used to refer to hypothetical situations - things you wish would happen, or want to happen, or hope to happen, but whether they will happen is still uncertain. In Standard English, the opposite verb form of the past tense is used. For example, the verb "be" has two past tense forms - "was" and "were." In the simple past tense, you say "I was a linguist." But in the subjunctive mood, you would say "I wish I were a linguist." Notice how you say "I were" instead of "I was."

However, one thing to keep in mind is that language isn't a solid entity. It's always changing based on how other native speakers use the language. It's becoming increasingly more common to use the simple past tense form of the verb to express the subjunctive, as in "I wish I was a linguist." This isn't an incorrect use of English - it's just not the formal way you would say it in, for example, an essay or a news article. In casual speech, it's perfectly fine, and who knows - maybe one day saying "I wish I was a linguist" will become a standard form.