Consonant clusters

Initial clusters in fu'ivla

• affricates (tc, ts, dj, dz)
• sequences C1C2C3 (all optional) where C1 is one of {c, s, j, z}, C2 is one of {k, t, p, f, x, g, d, b, v, m, n} and C3 is one of {l, r}, except sequences containing sx, jn, zn, tl, dl, nl, nr.

Medial clusters in fu'ivla

• any consonant followed by an initial cluster or one consonant
• in type III fu'ivla, also allowed CCVC-r/n-, CVCC-r/n-, CVC-r/n- followed by an initial cluster or one consonant

Vowel clusters

• In cmavo and fu'ivla:

Restrictive option

ai, au, ei, oi allowed always.
ia, ie, ii, io, iu, ua, ue, ui, uo, uu only at the beginning of a cmavo, cmene or fu'ivla.
No vowel triples allowed.
y not allowed next to a vowel.

Intermediate option

Long string of vowels allowed as long as pairs are always permissible diphthongs. Syllables break in pairs from left to right.
uy and iy allowed in cmene and cmavo.

(This is the option currently implemented.)

Permissive option

Any string of vowels allowed always. Syllables break in pairs from left to right for ai, au, ei, oi, ia, ie, ii, io, iu, ua, ue, ui, uo, uu, otherwise a single vowel forms a syllable. uy and iy allowed in cmene and cmavo.

Other options

. . .

Rafsi fu'ivla

Currently we allow any fu'ivla as final rafsi, and all those that can be non-final are allowed in non-final position. Fuhivla starting with vowel that can otherwise have a rafsi are allowed as initial rafsi.

Hyphens

CVC-y-

Currently the y-hyphen is allowed after any CVC-rafsi. Officially it is allowed only when it is required (i.e. between an impermissible pair or to correct a tosmabru failure).
RATIONALE: If one gets used to a lujvo like tosymabru, it is nice to be able to produce further formations like {naltosymabru} without having to remember to remove the hyphen in this case.

CVV-r/n-

Currently this is allowed only when it is required as the official rule says. However, it would not be a bad idea to allow it in any position.
RATIONALE: same as for the y-hyphen. If one gets used to the lujvo {li'erla'i}, it is a pain to remember that {nalyli'erla'i} is not a lujvo and one should use {nalyliela'i} instead. Allowing the hyphen always takes a little space away from fu'ivla, but makes things easier for the user.

doi-la-lai-la'i in cmene

Currently these syllables are not allowed in cmene unless preceded by a consonant or followed by a vowel or apostrophe. There is a proposal to drop the restriction altogether, and require cmene to always begin and end with a pause (as they are required in some contexts already).