Clashes with Compounds and Affixes

Version 1.1

A common feature in many natural languages is to drop or change a vowel when two words are combined or a word is suffixed. This tendency is also seen in a number of conlangs. This complicates the process of determining what root or stem word a word has been created from.
This is a convention that is to be avoided in Diinlang. This does pose the problem that the combination of words or the use of an affix might create unintended diphthongs. Let us consider some possible cases.
Diinlang has relatively few true suffixes and the words that may serve this purpose tend to begin with “-i” or “-e”. “-sio” is an obvious exception. For a word that ends in a consonant adding a suffix beginning with “-i”, “-e” or “-s” poses no problems. This leaves vowel endings. “-s” works with any vowel ending. “-i” potentially could form “ai”, “ei”, “ii”, “oi” or “ui”. “ui” poses no problems and “ai”, “ei” and “oi” are not vowel diphtongs in Diinlang, the constructions “ay”, “ey” and “oy” being used instead. For “ai”, “ei” and “oi” a Diinlang reader would know to insert a syllable break before the “i”. Terminal “o” and “a” in Diinlang tend to have the “oh” or “ah” sound. Terminal “-e” is pronounced in Diinlang so can be rendered as “eh”. Therefore when the joining of words results in “-ai-”, “-ei-” and “-oi-” they may be written as “-ahi-”, “-ehi-” and “-ohi-”. “-ii-” is a vowel digraph in Diinlang and for this we have the “rule of y and i”:
When a word that begins in “i” is being added as a suffix or compound to a word ending in “i” a “y” is added between the two “i”s.
For “-e” we see a similar situation. “ae”, “ee” and “oe” are not Diinlang vowel digraphs but can be written as “-ahe-”, “-ehe-” and “-ohe-” to avoid confusion.  “ie” and “ue” should pose no problems but can be written as “-iye-” and “-uye-” if desired.
There are a few suffixes that begin in “a-” and words or suffixes begining in “o-” or “u-” are possible. Where there is a conflict, or where it makes things clearer add a “-h-” to words ending in “-a”, “-o” or “-e” and “-y-” to “-i” and “-u”. The same process is used with prefixes that end in vowels. Perhaps the rule should be:
U and I go with Y.
It may, however, be simpler to adopt the universal rule that suffix endings take an initial “h” where a word ends in a vowel.
If it is desirable to break up an unwelcome consonant cluster between joined words the obvious remedy is to add a vowel. Esperanto uses “-o-” for this purpose but for Diinlang this may accidentally gender some words. Therefore “-u-” is suggested instead.