In
linguistics, the term
particle is often employed as a useful catch-all lacking a strict definition. In general, it is understood that particles are
function words that tend to be
uninflected — that is, words which do not have suffixes, for example, that reflect grammatical gender, tense or person. However, the term may have a broader definition.
Depending on its context, the meaning of the term may overlap with such notions as "
morpheme", "
marker", or even "
adverb" (another catch-all term). Like many linguistic concepts, the precise content of the notion is very language-specific.
The term ''particle'' is often used in descriptions of
Japanese and
Korean, where they are used to mark
nouns according to their
case or their role (
subject,
object,
complement, or
topic) in a sentence or clause. Some of these particles are best analysed as case markers and some as
postpositions.
Under the strictest definition, which demands that a particle be an uninflected word, English
deictics like ''this'' and ''that'' would not be classed as such (since they have plurals), and neither would
Romance articles (since they are inflected for number and gender).
On the other hand, if a particle is defined as simply an invariable word, interjections are to be classed as particles, as well as sentence-tagging particles like Japanese and Chinese question markers.
Interjections, sentence connectors, and conjunctions
Sentence connectors, tags or
tag questions (also called
sentence-finals), and
conjunctions connect to what has been said in a previous clause or sentence. These three types of grammatical particles (similarly to modal particles in some other languages) also reflect the speaker's mood and attitude toward what has come before in the conversation, or is likely to follow later. Because of their similar functions,
Interjections, sentence connectors, and conjunctions should be grouped together: