The Laws of Prayer /The Blessings of the Shema (69)

1. Ideally, one should recite the Shema in the Holy Tongue even if he does not understand the meaning of the words which he is saying, on condition that he understands the first verse, as if he did not concentrate on the first verse he has not fulfilled his obligation. (Shulchan Aruch and Mishne Berurah 61)

2. If he read the Shema in another language, and he understands this other language, he has fulfilled his obligation. However, it is incorrect to do this, as there are many words which we do not know how to translate properly. (e.g. veshinantam which has many explanations and totafos for which we do not know the accurate translation) (ibid)