NOT THE DEAD לא המתים

Why, during ברכת ק"ש in the morning,
the ציבור pauses in mid-sentence
and waits for the ש"ץ  to say
(ומקדישים(ן) וממליכים(ן
and then they all start together את שם?


              לא המתים

The  טור או"ח ס"א enumerates all  places where one should
pause when saying two words next to each other
where the first word ends with a Mem מ and the second
word starts with an Alef א.
One of the places he mentions is וממליכים את שם

The reason to pause is so that it doesn't sound as מת
(וממליך מת - he crowns the dead) 

The Chasam Sofer in the Hagohos (O.Ch 59) writes,
"At וממליכים את שם it is especially important to pause
so it shouldn't sound like וממליך מת because there
are cults who worship the dead.
This is also the reason why we stop in mid-sentence
and wait for the Chazzan to start את שם"

The בני עדות המזרח (Sephardim) do not pause because
they say וממליכין with Noon נ and not with a Mem מ

Nusach  (ספרד (אריז"ל also say וממליכין with a Noon נ yet
they do pause because they originally said וממליכים 
with a Mem מ so the original Minhag  of pausing stayed on
אמבצי