Stuart,

You are raising a very interesting point, and in fact the Ramban on the verse discusses your question.

The first thing that comes to mind is that the Targum might be alluding to the Gemara (Sukah 41a) that derives from the word "u'Lekachtem" that each and every Jew must take the four Minim -- it is not sufficient for a single set to be taken by the Beis Din (see Tosfos Menachos 27a DH u'Lekachtem). By using the plural form, the Targum implies that many sets are taken by many people, rather than a single set which is taken by one person. This seems to be the intention of the Ramban there as well.

But I think that there is more to it than that. You are touching on one of the basic grammatical differences between Lashon ha'Kodesh and Aramaic. In Lashon ha'Kodesh , the singular noun is often used to represent not just a single object but an entire species (see Midrash Bereishis Raba 75:6, Temurah 9a). Thus, instead of "a citron fruit," Pri Etz Hadar could mean "the citron fruit." Examples of this abound, see for instance, Bereishis 32:6 (Shor va'Chamor), Bamidbar 15:38 (Tzitzis) Devarim 25:15 (Even... Eifah). Aramaic has no such usage of the singular noun; thus in all of these cases the Targum uses the plural in his translation.

Here, too, the Targum understood that the four items mentioned in the Pasuk refer to the species and not to the object (perhaps because many of each item were taken by Klal Yisrael, as we mentioned above). Therefore it translated them in the plural.

One may ask that if this is true, why did the Pasuk describe the Lulav and Aravah with the plural nouns? They should also be written in singular, referring to the entire species. (This question, by the way, may also be asked on the opinion that maintains that we take on one of each of the four Minim, see Sukah 34b and Gemara there.) The answer might be that any of a number of species of palms and willows may be used for the Mitzvah, so even the species must be mentioned in plural form. (I wonder if this is an allusion that even the Canary Island Lulavim and weeping willows are acceptable for the Mitzvah.)

Perhaps a more plausible answer to this last question is that "Kapos Temarim" is singlular. Kapos means "bunched together," (like the Aramaic "Kafus"). Arvei Nachal may also be singular (as opposed to Arvos Nachal). Perhaps someone who knows Hebrew grammar better than I can offer his suggestions about this.

Chag Same'ach,

Mordecai Kornfeld