Whilst some conservative varieties of Celinese have retained the old preterite – which was formed by ablaut in some verbs and with a suffix in others – the past tense in Standard Elithoan Celinese is made in quite a simpler way, by adding –o– between the past verb root (which usually, but not always, is the same as the root of a verb in the infinitive) and its personal endings: thus, ceonís (you speak) becomes ceonoís (you spoke) and padathín (they fall) becomes padathoín (they fell).
This derives ultimately from the present perfect form of many early modern Elithoan Celinese varieties. In Períseg, for example, the present perfect form became used far more regularly than the preterite – in it, caithí (to work) became caithol ís (you have worked; you worked), subsequently caithow ís and eventually the modern caithoís (you worked.)
Here is a regular verb, crestí (to believe), fully conjugated in all its past forms:
crestoí - I believed
crestoís - you (sg.) believed
crestoío - s/he, it believed
crestoím - we believed
crestoíot - you (pl.) believed
crestoín - they believed
We must, however, highlight some frequent irregular verb patterns in the past tense:
Thanks to suppletion, sí (to be) conjugates in the past tense as one would expect fí (to make, to do) – i.e. as foí, foís, foío, etc. Whilst these forms can be used as the past tense of fí, it typically takes its past tense from foðí, a dialectical equivalent: foðoí, foðoís, foðoío.
There are many words that have sí or fí as a compound in them, such as cêfí (to join), nosí (to become), iofí (to copy) or nainsí (to attend). These are generally conjugated following the same patterns as sí and fí – i.e. as cêfoðoí (I joined) and nofoís (you became.) One must endeavour to avoid some speakers’ hypercorrection – conjugating all verbs ending in sí and fí in this way, even if they are not real compounds, such as befí (to strike, hit – from the noun bef, blow) or cailsí (to pay – from cé + aılsë, silver). These should be befoío (s/he hit) and cailseoíot (ye bought) rather than !befoðoío or !cailfoío.
There are two past tense forms of í: the far more common in Elitho is oí, but oloí is more common in Sairstír and elsewhere.
Many verbs that end in sí but which are not compounds containing sí (to be) optionally change their stem to keep the pronunciation of s as [ʂ] when o is inserted. As a few examples, brêsí (to fasten), syrosí (to provide) and pyrsí (to shoot) can become brêseoío (s/he fastened), syroısoío/syroseoío (s/he provided) and pyrseoío (s/he shot.) Spelling without the –e– insertion is, however, equally valid and common.
There is also a sizeable number of verbs which end in –oí – making o-insertion impossible. Celinese has no standard way of dealing with these verbs but no less than four admissible options: one can distinguish the past tense from the present by adding a circumflex to the o, as in lyntoín (they improve) → lyntôín (they improved); by adding an epenthetic –r– or –w– as in teiroím (we honour) → teiroroím/teirowoím (we honoured) or by turning the o of the root into a w, as in nothoínom (they delight me) → nothwoínom (they delighted me).
Less numerous are the handful of verbs ending in other broken vowel combinations, such as aí in draí (to turn) or saí (to dance), êí in lonêí (to negate) or wyêí (be wretched), the eí in lorneí (to glimpse) or the uí in buí (cover with mud) or nuí (contain). With all of these, the writer has the option to simply insert -o-, or to also add -i (after ê and e) or -w (after a and u) before the added -o-: thus "it contained eggs" could be ainrocím nuoío or ainrocím nuwoío, and "he valued it" can be sé gainaoío or sé gainawoío; whilst "we negated it" could be sé lonêoím or sé lonêioím.