Should syllable boundary be indicated in the phonetic and/or phoneme transcription?
- /dog.gi/ [dog.gi] 'doggy'
- /doggi/ [dog.gi] 'doggy'
Or does the choice of one of the two strategies have certain entailments for the analysis?
Including syllable boundaries between slash brackets depends on two things: what you mean by slash brackets, and the facts of the particular language. Slash bracket may conventionally be used for underlying forms, in which case you would be saying the syllable structure is underlyingly present, and that would be a highly controversial claim needing justification. Slash brackets are also used to refer to a pre-phonetic level, before the introduction of any predictable properties such as flapping or aspiration are thought to be in English. That is, a phonemic transcription only includes unpredictable phonemes, not predictable allophones. But the position of a syllable boundary is usually predictable by rule. Thus it depends on your ideology regarding the concepts "phoneme" and "predictable". As is well-known, flapping and aspiration are surface unpredictable in English, so from the perspective of predicting one phonetic property on the basis of another phonetic property, flapping and aspiration are not fully predictable, therefore English does have flap and aspirate phonemes. But from a pre-surface perspective, these properties and segments are fully predictable. Likewise, surface-contrastive positioning of segments with respect to syllables (as in Hebridean Scottish Gaelic) always appears to be ultimately predictable. The predictive factor may be something abstract and phonological in nature, such as whether a pre-consonantal consonant is moraic versus non-moraic (e.g. Blackfoot or North Saami).
Therefore, whether you should include syllable boundaries in a slash-bracket-enclosed transcription depends on what you are trying to say. If you mean that syllable boundaries are actually underlyingly present, then you should say that syllable boundaries are actually underlyingly present (and you should say why you believe that); if you believe that syllable boundaries are fully rule-governed but that those rules do not apply transparently to the surface level, then you should say that syllable boundaries are fully rule-governed but that those rules do not apply transparently to the surface level (and you should say what the source of opacity is). What you should not do is leave people to guess what your theory is regarding proper use of slash brackets and standards of phonemicity.
As for square bracket transcriptions, that again depends on what claim you are making regarding such transcriptions. A very narrow transcription of Blackfoot which was only informed by the facts of pronunciation would indicate that the language manipulates vowel tenseness and consonant duration in a fashion that suggests surface contrastiveness within comparable contexts (thus [ipiksit] "flee" vs [ipɪk:sit] "be anxious"). But that apparent surface contrastiveness goes away given some phonological analysis, if one admits the possibility of contrastive moraic status to consonants. In that case, /k/ in "flee" is non-moraic (and is not in the syllable coda), and the /k/ in "be anxious" is moraic (it is in the coda of the second syllable, and influences preceding vowel quality). Here too it depends on one's ideology of things in square brackets. If one thinks that square brackets should only contain measurable acoustic properties with a transparent, universal relationship between acoustic property and transcriptional symbol, then a surface transcription [i.pik.sit] or [ipik̩sit] vs. [i.pi.ksit]~[ipiksit] would not be legitimate (I use the syllabic tick under k to notate "surface moraic k"). But if one allows a more phonologically-informed transcription in square backets, this is a perfectly legitimate distinction. As with slash brackets, what you should do is be explicit your specific ideology, and what claim you are making, and don't leave people to guess what follows from including dots between slash or square brackets.
I think it could be either one, depending on the language. I have my own peculiar theory of syllables, which is a variant of Saussure's idea that syllable structure is a paradigmatic perspective which is reflected syntagmatically, i.e. in the stream of speech, by a phonetic segmental difference between explosive consonants (whose aperture increases) and implosive consonants (whose aperture decreases).
An obvious problem with Saussure's version of this theory is that aperture does not uniformly increase at the beginning of a syllable, nor uniformly decrease at the end. So my revision is to substitute stress/unstressed for Saussure's explosive/implosive. This is the SPE feature stress, which is defined for consonants (honest -- I checked), but not actually used for consonants, so far. We could identify it with the fortis/lenis difference, which is sometimes used for consonants.
So then we can identify as a syllable a syllabic segment together with any preceding stressed non-syllabic segments and any following unstressed non-syllabic segments.
This makes syllables phonetic, and also phonemic if there is a stressed/unstressed (fortis/lenis) distinction for consonants.
C.-J Bailey once gave an interesting argument for syllables being phonemic. He observed that in some southern dialects there is a distinction between May.a, the first name of the poet Maya Angelou, and Ma.ya, the Central American Indians. I could describe this as a difference in the stress of the y: the former y is unstressed and the latter one is stressed.
Unfortunately for this particular example, another plausible account is available. May.a might have the diphthong /ai/.
It very much depends on what you're trying to accomplish. If you're focusing purely on the segmental aspects (ie individual sounds) then syllable boundaries will not offer much additional information and they are not included in most phonetic transcription (they are very prominent in dictionaries where they play a different role).
Often syllable boundaries will enter the picture if you mark syllabic stress. However, the stress is really carried by the syllable nuclei, so the boundaries are no strictly speaking necessary. In English, there are at least two contradictory approaches to syllable boundaries (Cambridge vs Longman pronunciation dictionary) but in fact, the syllable boundaries are not all that analytically important. In other languages, this may be slightly different. But it is mostly a safe bet that vowel is the syllable nucleus so it is more important to mark syllabic consonants in your transcription.
Also, note. You are using the third method of syllabification which is based on orthography. This is used in phonics instruction but does not constitute transcription. Since, there is only one /g/ in doggy. Your choices are /do.gi/ or /dog.i/. Since there is supposed phonotactic constraint in English against unstressed open short syllables, only the second option is chosen by the two methods but I suspect even that is reading more into it than there actually is.