I've talked about (but not described) a main language I've been working on for 14 years, representing a far-future descendant of English. This is a different far-future descendant of English, starting from American but applying different soundshifts. I imagine this is about a millennium in the future, give or take.
/p b f v t d s z tʃ dʒ ʃ ʒ k g h m n r l/
The semivowels have been absorbed into falling diphthongs. Voiceless stops and /tʃ/ are strongly aspirated at the beginning of a syllable. /r/ = [ɹ].
/a e i o u/, with long versions /a: e: i: o: u:/ and diphthongs /ai au ei eu oi ou/. Falling diphthongs and triphthongs can be formed with onset /i u/ and any nucleus except for the sequences */ii/ and */uu/. Each vowel phoneme comes in oral and nasal versions. The realization of all monophthongs, regardless of length, is on the lax side: [æ ɛ ɪ ɔ~ʌ ʊ~ɯ].
Syllables have an onset, a nucleus, and a coda. The nucleus can be any vowel. The coda is (R)(O), where (R) = /r l/ and (O) = any obstruent. The onset is either /h/ or (C)(R), where (C) = (O) or /m n sp st sk sf sm sn/. In the written language, reflecting a recent standard, any onset, any nucleus, and any coda can combine to form a valid syllable, except that there is no distinction between short and long vowels in syllables with coda /l r ∅/; these are written long before /∅/ and short before /l r/. However, since then, a further soundshift has simplified liquid+glide clusters in both onset and coda. Any cluster of the form (R)iV or (R)uV simplifies to (R)V. Thus, <brieg>, "break," is pronounced /breg/. Moreover, any diphthong before /l r/ is pronounced as a long monophthong, creating a new distinction between short and long vowels before simple /l r/ codas in the process: <uoir>, "worry" is pronounced /uo:r/, distinct from <uor>, /uor/, "whir."
Nasalization and liaison:
Every nasal vowel in an open syllable followed by another vowel has liaison with [n]. Of note, nasal vowels that historically developed from Mod. Eng. /m ŋ/ are never open syllables; rather, they are analyzed as having homorganic codas. In a nasal environment, stop codas are nasalized. Thus, <bããb>, /bã:b/, "drifter" (from Mod. Eng. "bum"), is actually pronounced [bã:m], and <tẽp>, /tẽp/, "tempt," is pronounced [tẽm̥] or [tẽm̰].
Stress is not distinguished in writing. The language tends toward monosyllabic morphemes, through processes that turned bisyllabic words into monosyllables, but morphemes may still have any number of syllables. While there is still distinctive stress, it is weaker than in modern English, and especially in names, the biggest source of polysyllabic morphemes, people routinely place it wrong. The tendency is toward final stress, as the phonological processes that reduced syllable numbers dropped final unstressed syllables more than initial ones. However, sentential stress is strong and distinctive: particles never or almost never receive stress, and in some cases, which vowel they are analyzed as is entirely a spelling convention.
I have an entire set of soundshifts, but for this sketch, the important ones are as follows:
1. Every syllable with a nasal in the coda immediately following the nucleus nasalizes. After nasalization of the vowel, the codas are reanalyzed as /m n ŋ/ > /b ∅ g/ and in other cases the nasal is just dropped.
2. Every lone voiceless obstruent in the coda voices. This also happens in nasal contexts and behind /l r/. Before original voiced obstruents, including ones resulting from reanalyzed nasals, the vowel lengthens, with the exception of original /i/, in which case there's a merger (so "beat" and "bead" merge).
3. Vowel mergers and shifts: in oral syllables, /ju/ > /iu/ and other /u/ > /ʉ/ > /ui ue/ irregularly, /ɑ ɔ/ > /u/, /ʊ ʌ/ > /o/; length from step #2 is preserved, and new /o u/ is only weakly lip-rounded. In R-colored syllables, /ɑr ɛr ɔr ɝ ʊr/ > /ar er ur or or/, and also Mary = marry = merry. In nasal syllables, the mergers are still in effect, but /u/ remains in place, /ɑ ɔ/ > /o/, /ʊ ʌ/ > /a/, /æ/ > /e/, /ɛ/ > /e ɪ/, with the former more common and the latter restricted to interdialectical borrowings from the South. Remaining /ɛ æ/ is reanalyzed as /e a/, even though they are still lax.
4. Diphthong metathesis: /aɪ eɪ ɔɪ aʊ oʊ/ > /ia ie io ua uo/, with length preserved, except in open syllables (inc. open nasal syllables). If the onset already has a glide, it is replaced. Remaining unreplaced glides are reanalyzed from /w j/ to /u i/, with stray /wu ji/ > /uo ie/. With the bulk of original rising diphthongs gone, /i/ > /ei/ in all cases. From now on, original /ɪ/ is written as /i/, even though it is still lax.
5. Codas with more than one obstruent simplify. The obstruent that is retained is the first one, except for /ps ks/ > /s/ and /ts/ > /t s/ irregularly (/s/ is regular, but leaves a phonological gap of coda /t/, which is filled by interdialectical borrowings and international borrowings). Dentals are eliminated: /θ ð/ > /t d/.
6. Liquid metathesis: /l r/ in codas shifts to onset, provided the coda is not otherwise empty, and the onset contains no glides or liquids; if the onset is /h/, it disappears. This also happens intervocalically when the preceding syllable is stressed (when it is unstressed, it disappears); a resulting sequence of stressed vowel + unstressed vowel smooths to a diphthong if the unstressed vowel is /i u/ or has a glide (which would come from an original diphthong) and to a long vowel otherwise. If a vowel that wants to become a diphthong is /i u/ then it is lowered to /e o/. Thus, mellow > /'meluo/ > /mleu/, follow > /'fuluo/ > /flou/, Billy > /'bili/ > /blei/.
7. Second nasalization: every coda with a nasal consonant, coming from syllables that originally had a liquid + nasal coda, nasalize now. The sequence is important due to different vowel shifts triggered in rule 3. This nasalization happens even if the liquid is still there. The coda then undergoes the same reanalysis as in rule 1: burn > /brõ:/, berm > /brõb/, learn > /lõr/, squirm > /skuõrb/.
8. Monosyllabification: a minor syllable following a stressed syllable drops. If it has /i u/ and no coda then it turns the stressed vowel before it into a diphthong, with /i u/ lowering to /e o/ if they want to gain an offglide. If it has /l r/, the liquid jumps to the coda of the main syllable if there's space for it, and disappears otherwise: battle > /bald/, barrel > /ber/. A plain schwa lengthens the main syllable: tapa > /ta:b/. A nasal nasalizes the main syllable: seven > /sẽ:v/. An unstressed syllable before a stressed syllable drops provided the phonotactics allowed, with no consonants deleted.
The orthography stops here. One more soundshift happens, as described in the phonology section:
9. Liquid + glide smoothing in onset and coda. Onset glides drop, coda glides lengthen the vowel and then drop.
The language is analytic, even more so than modern English; soundshifts described below have stripped it of the remaining inflectional morphology. It tends toward monosyllabic, but this is not consistent. It also slowly tends toward isolating, with transparent derivational morphology written out as separate words.
The pronouns are 1p sg. <mei>, 1p pl. <uei>, 2p <iul>, 3p prox. <dĩz>, 3p dist. <dãd>. The 3rd-person pronouns derive from the Modern English demonstratives "this one" and "that one." <mei ~ uei> is the only place in the language with grammatical number. There is no case distinction: "I sabotage us" is <mei hied uei> (<hied> < "hate"), even though <mei> transparently derives from "me" and <uei> from "me."
The particle <ul>, from Mod. Eng. "all," can be appended after every noun and every pronoun except <mei> to denote pluralization; <uei ul> is grammatical, and carries an intensifying meaning over plain <uei>, like "we all" vs. "we." Note that the second person comes from y'all, but is not inherently plural, and can be pluralized as <iul ul>, "all y'all." <ul> does not appear after any noun modified by a numeral.
Syntax is largely unchanged from Modern English. The big change in word order is that possessives now strictly precede possessors, with the particle <oo> (< "of"), typically pronounced [ə]. Adjectives still precede nouns, but it is increasingly acceptable to flip the word order. Compound nouns remain head-last by default, but it's possible to flip the order with <oo>, usually pronounced more clearly as [o] to avoid ambiguity. A horserace is a <ruz riez> or a <riez oo ruz>, a racehorse is a <riez ruz> or a <ruz oo riez>. In rapid speech people might pronounce <ruz oo riez> as [ɹuz ə ɹez] when describing a race's horse (e.g. a horse belonging to a particular race) and as [ɹuz o ɹez] when describing a racehorse, but this is not done in careful speech, and in any case where ambiguity may arise, speakers prefer to default to head-last compounding.
Derivational morphology has eliminated the original -ing and '-er suffixes. -er is replaced with <mẽẽ>, < "man." -ing just drops in gerund forms: meeting > <meid>. Past tense is formed periphrastically with <haav>, now exclusively a tense marker; the verb to have is <õũ>. More tense/aspect particles: <iuus> < "used to," indicating imperfect past; <haad uil uood>, as in Modern English. None is obligatory when the time of the action is specified: <iers dei mei gou uog>, "yesterday I went for a walk"; <iers dei mei haav gou uog> is grammatical but uncommon.
Postpositions have been eliminated, and replaced by prepositions. "Seven years ago" is <pur sẽẽv ieir>; <pur> is a highly irregular reflex of "before," with intermediate form /pfur/ leading to the apparent fortition, coming from overzealous elision of pretonic syllables.