When one reaches the phrase "Hayom, 'Al Lebabekha" (today, on your hearts), in the Shema', one must take care to pause between the words "Hayom" and "'Al Lebabekha". The reason is that it should not appear as if one is saying, "we only have to love G-d today and not tomorrow", or, "the commandments only need to be in one's heart".
The word "Nishba' " must have the letter ע' ('Ahn) pronounced correctly. If it is pronounced like a ה' (Heh), it changes the meaning from "G-d swore" to "was captured", Heaven forbid.
When saying the word "Tizkeru", one should pronounce the letter ז' (Zahn) clearly, so that it should be obvious that it means "remember" and not "Tishqeru", or "Tiskeru", which would make it appear that we are only serving G-d in order to receive a reward. So too, when saying "Uzkhartem", one must be particular about pronouncing the letter ז' (Zahn) clearly and correctly.
(See Shulhan 'Arukh 61:15, 16. Mishnah Berurah, ibid., 32)
shma yisroel, shema' Yisrael, misread or misunderstood