Science Fair Project Encyclopedia An interjection, sometimes
called a filled pause, is a part of speech that usually has no
grammatical connection to the rest of the sentence and simply
expresses emotion on the part of the speaker, although most
interjections have clear definitions. Interjections are
generally uninflected function words and have sometimes been
seen as sentence-words, since they can replace or be replaced by
a whole sentence (they are holophrastic). Sometimes however
interjections combine with other words to form sentences.
Interjections are used when the speaker encounters events that
cause these emotions — unexpectedly, painfully, surprisingly or
in many other sudden ways. But several languages have
interjections that cannot be related to emotions. The word
"interjection" literally means "something thrown in between"
from the Latin inter ("between") and jacere ("throw").
Conventions like Hello and Goodbye are also interjections, as
are exclamations like Cheers! and Hurray!. In fact, very oft