A situation that arises regularly in the Shema' that requires much attention, is when a word ends with a Meem Sofith (ם) and the following word begins with an Aleph (א). This occurs multiple times, as in וְשַׂמְתֶּם אֶת (Wesamtem Eth) and וּקְשַׁרְתֶּם אֹתָם (Uqshartem Otham) and וּזְכַרְתֶּם אֶת (Uzkhartem Eth) and וְלִמַּדְתֶּם אֹתָם (Welimmadetem Otham), and וּרְאִיתֶם אֹתוֹ (Urithem Otho), and וַעֲשִׂיתֶם אֹתָם (Wa'asithem Otham).
One must be very careful to have a short pause between the words. If one does not have a separation between the two words, the last letter of the first word and the first letter of the second word will form either the word "Motham", which means their death, or "Meth" which means dead, Heaven forbid.
Additionally, it is appropriate to read the Shema' with the Ta'amim (cantillation notes). It is correct to do so whenever Torah verses are used in the prayer, and in the case of the Shema', the correct emphasis that comes from doing so, also affects the meaning. This is the custom of Sephardim. While most Ashkenazim do not read the Shema' with the Ta'amin, there are some who are particular to do so.
(See Shulhan 'Arukh with Rama, 61:21, 24)
Sheam Yisrael, Shema, Shma, joining words in the shema', reading the Shema with Taamim, reading the shma with the trop, trop, ta'amim