Do I have to speak out the targum if I’m using English translation?
It is controversial if one can be yotza targum by reading an English translation. The Bais Yosef writes that reading Targum is unique in the sense that it is the correct translation and considered given at Sinai. Therefore, one should specifically read targum. Others however say that if one can’t read the Targum he may read it in English. Therefore, if possible you should read the targum. Reading the targum at the beginning can be daunting, but with time you’ll get used to it, and it will also improve your reading skills. If however it is hard for you there are poskim to rely on. See sources.
There is controversy among the poskim if one has to understand the meaning of the targum or not. R’ Eliyashiv, and R’ M. S. Klein hold that one has to understand the targum, however R’ S. Z. Auerbach (Halichos Shlomo Tefillah 12 ftnt. 48, says that although it is definitely preferred to understand it, however even if it isn’t understood one is till yotza. This is also the opinion of Yichave Daas 2-37 brought in Shmiras Shabbos Khilchoso 42 ftnt. 115, the opinion of R’ C. Kanievsky shlita (Derech Sicha vol.1), and the opinion of R’ S.Kaminetsky (Kovetz Hilchos Shabbos 1 19-31).
Regarding if one can be yotza by reading the English translation, this is also controversial. R’ C. Kanievsky, R’ A. Nebezahl, and R’ Y. Cahen shlit”a hold that one is not yotza with reading the English translation, but on the other hand see Teshuvos Vhanhagos 1- 261 who was asked regarding a baal teshuva who doesn’t understand the targum at all that he may read it is English. Also see Yagel Yackov (Dardak) letter 66-7 in the name of R’ D. Feinstein shlit”a who brings the Mishna Berura 285-5 that one who doesn’t understand even Rashi should at least learn it with German translation. R’ Yackov Skotzylos shlit”a (author of Ohel Yackov on Shmanim Mikra) writes that this is also the opinion of R’ S. Doblitsky zt”l, and the opinion of R’ A. Shleisinger (Author of Shoalim V’dorshim), that although it is better to read the targum, if it is very hard one may read it in English.