So I hope this is the right place. What I've done with Latin and Sindarin is more complex than a mere cipher. Its grammar includes things from English, Spanish, Latin and Sindarin. The vocabulary is mainly obtained through a set of rules from Latin roots or Latin-like adapted roots. Consequently the lexicon is something in constant expansion that can get richer anytime, having words coined with a systematic methodology.
This is what I wanted, since my original intention was to have something useable anytime with the feel of Sindarin and I'm too lazy to invent a whole lexicon (plus, in this case, you already have Tolkien's Sindarin for that - I'm not Tolkien, and this is done totally out of admiration and respect for his work). There are a few words directly from Sindarin or invented by myself, but that's a minority. It won't be uncommon to find irregularities as it's not yet settled. I haven't written any grammar before, so I'll go step by step here.
I've seen this thing being called a bogolang, a hybrilang, etc. but I chose not to include any of these names in the title since I saw no general consensus on the net and I thought it may give a misleading first impression. In any case, I hope what it is is clear from the previous description.
The source of vocabulary
First of all, one needs the lexicon ready. This is the "ciphering" part. In order for something to be like Sindarin, it has to come from something which is, historically, as the language which evolved into Sindarin. This language was Common Eldarin, in one of its stages. It has a phonology not very distinct from Latin; nevertheless, some minor adaptations are needed. Once these adaptations are made, I'll say the roots are in "Latin". Firstly, gemination is lost as distinctive in plosives. Secondly, the phoneme /w/ is replaced by /gw/ (vinum /winu/ to *gwinu /gwinu/), and so the sequence /g/ + /w/ is a new phoneme /gʷ/ (sanguis: /gwis/ to *sangue /gʷe/). This minor distinction is very relevant.
This is what "Latin" phonology looks like, more or less:
Nasal: /m n/ <m n>
Plosives: /p b t d k g kʷ gʷ/ <p b t d k g qu gu>
Fricatives: /f s/ <f s>
Liquids: /r l/ <r l>
Semivowels /j/ <i>
Vowels: /a e i o u/ <a e i o u> Diphthongs: /ai oi aw/ <ae oe au>
From here we can get the hybrid conlang's words with a regular set of sound changes. The consonantal changes are more regular and realistic than the vowel changes. Vowels, having less room to vary, follow some irregular rules that I made up without any basis on Sindarin. But before the sound changes, I'll say how roots are extracted from each part of speech.
Nouns and adjectives Take the accusative form and drop -m, the result should end in one of the three vowels -a, -e or -u. For adjectives do the same with masculine gender (gender is going to be lost and it doesn't matter anyway, because all final vowels will fall later). For example:
porta, -ae f. - *porta door
filius, -ii m. - *filiu son
rex, regis m. - *rege king
senatus, -us m. - *senatu senate
bos, bovis m. - *bogwe cow, bull
malus, -a, -um - *malu evil, bad
vetus, veteris - *vetere veteran, old
prudens, prudentis - *prudente prudent
acer, acris, acre - *acre sour, bitter
Verbs There are two verb classes: a-verbs and i-verbs or primitive verbs. For a-verbs, which encompass the Latin first conjugation, the root ends in the infinitive's a, dropping the -re from -are. Even though Latin verbs are listed by their first person singular present indicative tense, I will list them by their infinitives here because it's more convenient. For i-verbs, which encompass the rest of the verbs, drop the whole infinitive ending and append an -e:
amare > *ama- love
laudare > *lauda- praise
loqui > *loque- talk
timere > *time- fear
facere > *face- do, make
emere > *eme- buy
partire > *parte- split
venire > *gwene- come
Prepositions, adverbs and other parts of speech
For these, the root normally coincides with the "Latin" form resulting from mere phonological adaptation. Adverbs are largely interchangeable with adjectives in the conlang, or can be derived internally (I'll talk about that later for the conlang's internal morphology). However, most prepositions and other parts of speech do not come from Latin and are either invented by me or taken directly from Sindarin. Among words used as in Latin, we have:
bene > *bene well
inter > *inter between
sive > *sigwe or
Once the word is phonologically adapted and we have the proper root shape, we can apply the sound changes for the consonants and change the vowels in a special pattern. I'll describe these next post.