Is a full stop, represented by the graphical character '.', a morpheme?
I haven't found a source either confirming or denying this, but the examples I've seen seem to indicate that the answer is no.
Linguistics Stack Exchange is a question and answer site for professional linguists and others with an interest in linguistic research and theory. It only takes a minute to sign up.Sign up to join this community
The first answer I drafted was similar to what boiko ended up writing, but I abandoned it on realizing what you've confirmed by your comment: you're not asking about the linguistic status of the symbol "." but about what that symbol represents.
Another way of asking this question might be, "How do we know when a sentence ends?"
To my way of thinking, there are two possible directions to take:
Your question can now be understood as whether the symbol "." represents a distinct element (hypothesis 1) or is purely conventional because there is no separate element (hypothesis 2).
Hypothesis 1 supposes that there's an element somewhere in the sentence carrying information about the sentence's endpoint. Normally this would indeed be a morpheme. For example, in the word "runs", run-s, the second morpheme -s carries syntactic information: 3rd person singular simple present tense.
One problem we run into is that there is clearly no segmental content to mark a sentence end; that is, there is no additional sound at the end of a sentence that we could say is the realization of such a morpheme. There isn't even a segmental sound change (because some morphemes change the realization of nearby phonemes, such as German umlaut).
How deep a problem this is for our first hypothesis depends partly on what you think about zero morphemes. But even if we were to assign a null realization to our sentence-ending morpheme, we would have a difficult problem in that zero morphemes are inferred through contrast with non-zero morphemes. But there is no separate segmental content for a sentence continuation either.1
Hypothesis 2 supposes that something about the other elements in the sentence serves as our indication of where the structure is. Specifically, the suprasegmental realization of the sentence. This term covers a broad range of phenomena from pitch to timing.
According to this hypothesis, we should expect someone's intonation patterns to change when they come to the end of their sentence, and/or their volume to shift, and/or their vocal quality to shift (e.g. switching to vocal fry), and/or their pace to slow down or speed up.
What do you think? Do those signs sound familiar? :)
Hypothesis 2 is the currently accepted one. A direct answer to your question, then, would be no, the full stop does not represent a morpheme, but a set of phenomena affecting the realization of the other morphemes in the sentence.
In fact, we use all the ones listed and we use them to make a great number of contrasts. Just for fun, here are six different intonations of the same sentence (or fragment!): the same morphemes, but different prosody. How would you characterize the information conveyed by each variation?
Incidentally, it's probably because these syntactic clues are contained in the suprasegmental layer that so many orthographic signs have been added to the alphabet. How else can we capture that information? We try to get a few of them with skillful use of the period, the exclamation mark, the ellipsis, the question mark, the semicolon, the comma... and the correspondences between this conventional, fairly recent linguistic system to the natural acrobatics of the human voice is certainly a worthwhile thing to examine, but it's been the stylists, not the linguists, who've been doing so.
1 A reply might be that we do have morphemes for sentence continuation: conjunctions like "and", "or", etc. While these do serve that function, suprasegmental information is both sufficient and overriding. The fact that people have to be taught by confused high school English teachers not to start a sentence with "and" or "but" suggests that, in fact, we have no problem ending a sentence as far as the intuitive cues are concerned and just using the conjunction to introduce the next sentence.
Morphemes are sequences of phonemes that have meaning. A full stop or period doesn’t correspond to any sequence of phonemes; so it’s not a representation of a morpheme. It is however related to meaning, in a way. This is because meaning in language doesn’t exist just at the level of morphemes.
Punctuation is more or less related to linguistic features at the levels of syntax and prosody. In the most basic case, full stops more or less correspond to the descending intonation used at the end of conclusive utterances. Compare the difference in the pronunciation of “ Really? ” vs. “ Really. ”; it's the same morpheme, but said out loud with different pitches, which colour the meaning in different ways.
However, one must put emphasis on that "more or less". Punctuation has its own rules that are not quite the same as those of linguistic grammar. There's a rough correlation between linguistic syntax/prosody and written punctuation, because punctuation was originally modelled on those. However, modern writing has long since evolved into its own system, which is more than merely a transcription of speech. Geoffrey Nunberg discusses this in The Linguistics of Punctuation in great detail.
Briefly, the unit called a "sentence" in texts isn't really the same as grammatical sentences. Nunberg calls the former text-sentences. A text-sentence may contain several linguistic sentences…
The poor cried; Cesar wept.
Or may span less than one, in fragments:
The L9000 delivers everything you wanted in a luxury sedan. With more power. At a price you can afford.
And these cause various stylistic effects that should be intuitively clear to you. The main function of the period is to mark the end of a text-sentence. It is then something internal to text-grammar, the tacit (unconscious) knowledge we use when processing written language.