Aside from the obvious situations where someone can have genuinely bad speaking skills or just read from slides or handouts, there are several other annoying speaker habits worth noting. At a lunch meeting today a woman making a brief announcement was playing with a rubber band while speaking - I'm not even sure she realized she was doing it - but it was being stretched and twisted between her hands while she was talking. Other annoying habits are speakers who click their pens or jingle keys/coins in their pockets while they're talking. Or those who refuse to use a microphone even if there is one ready for them as they announce they're "sure" everyone can hear them.
Distracting noises and actions can distract the audience. I wonder if their friends or hosts at meetings mention it to them?