Each morning, before Baruch She'amar, we declare twice, "Hashem Melech, Hashem Malach, Hashem Yimloch Le'olam Va'ed" – "Hashem is King, Hashem was King, Hashem will be King for all eternity."
As this proclamation declares G-d's Kingship over the universe, one should ensure not to leave the synagogue during this recitation, so as not to give the impression that he does not agree that Hashem is King (just as one should not leave the synagogue when the congregation recites "Shema Yisrael").
The word "Melech" is pronounced "Mi'le'el" – meaning, with the emphasis on the first syllable ("ME-lech"). By contrast, the word "Malach" is pronounced "Mi'le'ra" – with the emphasis on the second syllable ("Ma-LACH"), and the word "Yimloch" is similarly pronounced with the emphasis on the second syllable ("Yim-LOCH").
One should ensure to pronounce these words properly, stressing the correct syllable. Sometimes the Hazzan chants this proclamation in a melody, and while fitting the words to the melody, he and congregation might mispronounce them. It is important to be cognizant of the correct pronunciation and place the stress on the proper syllables.