Lukewarm takes:
Phonology should be significantly optimized for aesthetics, as long as the loglangishness doesn't suffer. The sheer ugliness of Lojban is IMO a big reason why it's not as popular as it should be. As a second point on the "optimize for popularity" topic, if there's ever a conflict between ease of pronounceability for English speakers versus any other language, err on the side of English.
Having any character not in the a-z range has two major drawbacks – the first is that it's going to be really annoying to type for a vast amount of people. Typing "Ņ" with my Swedish keyboard requires me to do the awkward hand movement of pressing AltGr+, then releasing the keys to press Shift-N. I'd rather have it be any other character that's available.
Secondly, and this applies to the apostrophe too, is that a lot of things that has to do with computers doesn't deal with those characters very well. Anything with e.g. an apostrophe will be hard to google for, it will often need escaping if it's inserted in a string, and likely won't be useable as tokens (e.g. a variable name in programming languages, a browser user-agent, computer usernames...) – and even in the cases where it is usable, it requires ugly hacks to get working (domain names, filenames).
Hm, you're right about the apostrophe. Toaq and Eberban use the apostrophe for the glottal stop. Lojban uses the period. What other glyph do you suggest? x? Of the letters in the English alphabet, the following are not used by Sekko: j f v w x.
Yeah, x seems the most appropriate candidate. It sufficiently rare in English to not trip people up too much, from a cursory glance at Wikipedia it's at least used for that purpose in Pirahã, and it even looks like a little pictographic "stop" symbol.
Edit: Oh, apologies, I completely misunderstood the part where "ņ" was actually written with the letter "q". Nevermind that part!
I would prefer if the post would contain the argument for why you make the choices in the language design that you make and not just states which choices you make.
In truth, the phonology is unimportant for making a loglang. For making an artlang or an auxlang (auxillary language), phonology is very important -- but not for loglangs. It's more of an aesthetic choice. Also, I'm not very good at phonology. I used to have a loglang partner who co-created the language with me, but she left early on because of mental health issues.
Conlang making is weird because it's less "design" and more like...feeling what feels right. There are certain things that seem correct and certain things that feel wrong based on which elements you've put down previously. You "fix" some points, and the rest of the design falls into place. In that sense, it's more like discovery. I'll tell you a little history about Sekko's phonology, though.
Sekko originally had a Finnish-esque phonology. Voicing distinction on plosives and affricates (we had tʃ dʒ), no voicing distinction on fricatives. At that time, we also had the labiodental fricative f. Vowel and consonant length distinction were already present. The approximants j w were treated as separate consonants and not treated as diphthong allophones -- diphthongs were instead pronounced with hiatus. The palatal nasal ɲ was also a separate consonant and not an allophone.
There was no voicing distinction on fricatives because we didn't want a v-w distinction (and because Finnish didn't have it either, but we soon stopped caring about faithfulness to a Finnish-esque phonology. Now it's more of a weird mix of Japanese and Mandarin because of the labialization and palatization of consonants).
Now, this was all fine, except that I didn't like how diphthongs had to be pronounced with hiatus. It's much better to permit them to be said with glides. That entailed removing j w as true consonants.
I didn't like that we had no ʒ but we had dʒ. The labial fricative was removed, and voicing distinction for fricatives permitted.
Because consonants can be palatized now, we had a tj tʃ distinction (think of English "tube"). I didn't like this, so the affricates also lost their status as true consonants and became allophones.
Now there was less reason to remove ʃ and ʒ (I actually might re-add them). It's the same situation as before, where there was a sj ʃ ʃj distinction. I didn't like that very much, so the post-alveolar fricatives had to go.
In truth, the phonology is unimportant for making a loglang. For making an artlang or an auxlang (auxillary language), phonology is very important -- but not for loglangs. It's more of an aesthetic choice.
I don't see any reason to think of strict categories like auxlang and loglang that are mutually exclusive.
The notion of a loglang means that you want your language to fulfill certain criteria and are thus willing to make it a bit harder to learn, but that doesn't mean that ease of learning the language is irrelevant.
Lojban itself goes through exercises like making it's terms resemble existing words to be easier to learn.
I know it's phonology and spelling rather than phonetics you're mainly talking about in this post, but you talk about allophones anyway, so I feel I may ask this. Will tone / pitch or stress play a role in the language?
I thought very much about having a simple high-low tone accent system like Japanese or Ancient Greek. It would make SSM very, very easy and simple, given that I can just make word beginnings take the high tone and continuing syllables take the low tone (or the reverse). However, I'm unduly biased against tonemes, so I didn't include them. Toaq is a loglang with a seven tone system, if you're into tonemes.
Stress will not. I already have phonemic vowel length and consonant length. The only remaining differences possible are tone (which is pitch accent), and volume. I don't want to have volemes (do those even exist?).
In the rest of this article, the following notation is used:
Crefers to a standard consonant.Vrefers to a standard vowel.Ccrefers to a geminated/long consonant.Vvrefers to a long vowel.Consonants
Phonemes in parentheses are permitted allophonically (see further down).
All consonants may geminate and have length distinction, except for
hand'. Geminated consonants are written twice. The length of a geminated consonant is twice the length of a short consonant.Due to the structure of allophones (see below), the following consonants also cannot geminate:
wjʃʒtʃdʒɲThe geminated form of the alveolar tap is the alveolar trill. At least two taps must be spoken for the alveolar trill.
Vowels
Vowels have length distinction. Long vowels are written twice. The length of a long vowel is twice the length of a short vowel.
Only /Vi/ /iV/ /uV/ /Vu/ diphthongs are allowed. Length distinction is forbidden in diphthongs, and all vowels in diphthongs are to be pronounced short. (e.g. /uua/ is forbidden)
Allophones permitted:
Syllable structure
Sekko has a CcV+(C(c)) syllable structure. Consonant clusters may only occur across syllable boundaries; consonant clusters cannot occur in the same syllable (ignoring approximants). The nucleus may be of arbitrary length, so long as all pairs of vowels are legal diphthongs. (e.g.: In /kuioua/, /ui/ /io/ /ou/ /ua/ are all legal diphthongs.)
Null onsets are forbidden.
See this Google Sheets chart for a chart of permitted consonant clusters (sadly, I cannot figure out how to embed pictures in the editor).
Orthography
Sekko uses Latin script as of now. Spaces are optional (the self-segregating morphology system is sufficient to find word boundaries unambiguously) but highly recommended for ease of reading.
Punctuation, such as the question mark to mark interrogative sentences, commas for connection, and periods for sentence endings is optional (the sentence fence suffixes are sufficient to find sentence boundaries unambiguously).
Capitalization to mark sentence beginning and names is optional.
The apostrophe, representing the glottal stop, has no upper-case form.