Ą

In some dialects, word-final ą is also pronounced as /ɔm/; thus, robią is occasionally pronounced as [ˈrɔbjɔm].

Polish ą sound evolved from a long nasal a sound of medieval Polish into a short nasal o sound in the modern language. The medieval vowel, along with its short counterpart, evolved in turn from the merged nasal *ę and *ǫ of Late Proto-Slavic.

Another explanation is connected to the adoption of the Old Czech-style orthography of the Latin alphabet to write Polish at the turn of the 16th century. In Poland-Lithuania, Latin still dominated in writing in the Kingdom of Poland, and the Cyrillic-based vernacular of Ruthenian had been in official use in the Grand Duchy of Lithuania since the 13th century. In pronunciation, the Church Cyrillic letter big yus (Ѫ ѫ) corresponds to the pronunciation of the Polish ą. However, it is little yus (Ѧ ѧ), which is phonetically similar to ę and, more importantly, shares visual resemblances with the Latin alphabet initial letter (A, a) plus an ogonek, that some believe led to ogonek's introduction. This, according to proponents of the theory, resulted in the letter ą for denoting the nasal o, when it logically should have been ǫ rather than ą. When the ogonek had already been in place as the diacritic for marking nasality in vowels, it was appended to e, resulting in ę for nasal e.[1]

The letter often alternates with ę.

• 'tooth': ząb → zęby ('teeth'),
• 'snake': wąż → węże ('snakes')
• 'husband' in nominative: mąż → z mężem ('with husband', in instrumental case)
• 'weight': ciężar → ciążyć ('to weigh down, to be a burden'),
• 'month': miesiąc → miesięczny ('monthly'),
• 'a judge': sędzia → sądzić ('to judge, think')
• 'row' in nominative: rząd → cztery razy z rzędu ('four times in a row', genitive case)

However, in words derived from rząd ('government'), the vowel does not change. Thus, rządu (genitive of rząd) retains the ą, e.g., rozporządzenie rządu ('government's ordinance').