Łęczyca and Sieradz have even been considered as one group due to the large number of similarities by Eugeniusz Pawłowski and others.
A shift of ra- > re- common of northern Polish dialects is found only in a few fossiliziations in Łęczyca now.
More commonly a lack of an ablaut in verb forms can be found, usually as the result of analogy: bierom (biorą), przyniesły (przyniosły).
Word-finally it denazalizes to -e. Before l, ł, raising may occur and then denasalization, resulting in forms such as wyjyłam (wyjęłam).
Word-finally it can most commonly decompose to -om, be realized as in standard Polish, or rarely, on the border with Masovia, denazalize to -o.
Raising before liquids, especially nasals, and less often before r, l, ł, is present as well, but also becoming uncommon: eN > yN, aN > oN, and sometimes oN > uN, and somewhat more commonly or > ur.
[2] Labialization of initial o and ó (from prenasal raising) to ô is rare here, but may be more common in certain regions such as Dobrów.
Often initial ch plus a consonant changes to k: krzciny (chrzciny), and the group kt changes to cht, and tk to tch: zatchane (zatkane).
Some Masovian traits may be seen regionally: decomposition of soft labials may occur (found with a single speaker in Tum), simplification of clusters resulting from this decomposition: cojek (człowiek), pojado (powiada) (found in Tum and Dobrów), św’, ćw’, dźw’ may be realized as św, ćw, dźw (found with a single speaker in Tum as well as many speakers in Dobrów), and a hardening of -mi, especially in instrumental plural endings and the dative singular of ja (found ni Tum); hardening of soft ḱ: occasional hardening of li > ly, usually the result of raising pochylone e: mlykim (mlekiem).
[2] The feminine genitive/locative singular of adjectives, pronouns, and numerals and the comparative of adverbs may e -ij/-yj or less commonly -i/-y due to sound changes.
Similarly, and often preferred for dialectal stylization, is the ending -śta, -ta, extracted from the old dual; used for the past tense in Tum and occasionally for the imperative in Dobrów.