Once we mispronounce letters, such as equating chof and ches or equating aleph and ayin, we can get into even more trouble when misemphasizing.
Bentching - I think this is a common one. וְזַרְעוֹ מְבַקֶּשׁ לָחֶם. What happens when it is pronounced melira? It sounds like לָכם.
I had once when I heard megillah, by גַּם אֲנִי וְנַעֲרֹתַי אָצוּם כֵּן - he said אָצוּם meliel. I was wondering if I was yotzei or not... (Lemaaseh some ladies in my cousin's building needed to hear the megilla so I volunteered to lein it for them.)