Halakha Bilangan 15:40: Chafetz Chaim & Mishneh Torah, Reading the Shema

Blessed is the L–rd, the G–d of Israel, who has separated us from all the peoples and given us His Torah and brought us to the holy land so that we merit fulfilling all of His mitzvoth. His sole intent was for our good alone, so that through this we become holy unto Him — viz. (Numbers 15:40): "So that you remember and do all of My mitzvoth and be holy unto your G–d" — and so that it be in our power to receive the effluence of His good and the abundance of His lovingkindness in this world and in the world to come, as it is written (Devarim 10:12- 13): "What does the L–rd your G–d ask of you, but… to keep the mitzvoth of the L–rd and His statutes which I command you this day to do good unto you?" (See the Ramban there to the effect that "to do good unto you" reverts to "What does the L–rd your G–d ask of you.")

How should care be exercised in enunciation? One should take heed not to sound a letter with a strong Dagesh as if it were without such a Dagesh, nor a letter without a strong Dagesh as though it had such a Dagesh; nor sound a letter with a Sheva mobile as if it were immobile, nor, vice versa, sound a letter with a Sheva immobile as if it were mobile. Hence also, a pause should be made between two words, where the first of the two words ends with the letter with which the one immediately following it begins. For example, in reading the words Bechol levavcha, a pause should be made after the word Bechol, before reading levavcha. The same practice should be observed in the case of Va-avadtem meherah and Hacanaf pesil; so too the zain in tizkeru should be pronounced distinctly. One should dwell on the Daleth in Ehad a sufficiently long interval to enable one to acclaim God as Sovereign in Heaven and on Earth and towards the four cardinal points of the compass. The Heth in Ehad should not be pronounced hurriedly, for then the word would sound Ee had^*Not one..