Hola Patrice!
De nada! :)
We don't use ananás for pinneapple here in Mexico, but i know some countries in south america do.
Regarding the Tomatoes, el Jitomate and Tomate, mean the same thing, for what i have noticed , people in southern Mexico use Jitomate more than Tomate, but of course, everyone knows where are talking about the Tomatoes. So, Jitomate is not a type of Tomate, is just another name.
The most popular type of Tomatoes we use here in Mexico are Tomate Saladette, Tomate Roma and Tomate bola. The state of Baja California (where i live and was born and raised) is one of the top producers of tomatos in Mexico, alongside the state of Sinaloa (the state even has a baseball team called "Los tomateros de Cualiacán" which is the capital of Sinaloa), i am not a big baseball fan, so i just know they are one of the best baseball teams in Mexico. By the way Culiacan names also comes from nahuatl.
I've never really studied Nahuatl, during our primary school, while studying Mexico history and also Spanish, most teachers pointed out the importance of the pre-columbian indigenous people (amerindians) in the formation of our culture, way of living and language, so i learned a few words, and took some interest in learning about the Mayans and the Aztecs, primarly. Our national dishes, our mexican spanish and our flag (the eagles, eating a snake, standing in a nopal, another nahuatl word, was found by the Aztecs and they decided to establish Mexico City there, or Tenochtitlan, as it was called on those days), have direct conection to those ancient civilization, even our country's name is believed to be derived from Nahuatl, either from "Place at the Center of the Moon" to "The place where Huitzilopochtli lives" , this crazy Huitzilopochtli word, is the name of an Aztec God, and even for us Mexicans is a bit hard to pronounce hahahah.
About Italian, i also, havent really studied it in a formal way, i do know some phrases, words and it is amazing how similar is to spanish, since they both derived from Latin, same thing with portuguese (which i also understand to some extent) French (i have studied in an informal way, and even downloaded the Rocket French free trial) and Galician (which is very very extremly similar to spanish). The only "formal" languages i have studied is English and German...and well, technically speaking also Spanish, even if it is my native language, and which i never really stop learning and have been focusing a lot on grammar, ortography and also the different regional variatons (For example Mérida speaks a lot different than people in my city, this includes some expressions, and primarly the accent).
Anyway!!! i started writing and when i realized i had a ton of words here hahaha, i hope i havent bored you much!.
Here is a list of nahuatl words, which include words you probably know, like Tamales, atole, elote(corn), Chipotle, jalapeño, Jicama, Mezquite, and even Marihuana (which i just discovered to have some nahuatl rooth, i will investigate haha)
http://en.wikipedia.org/wiki/List_of_Spanish_words_of_Nahuatl_origin
Saludos desde Tijuana, Baja California. Endlich freitag und ich wunsche dir einen schonen start ins wochende!