tha a’ phiseag òg
(piseag is a feminine noun, as all diminutives with the -ag suffix are feminine)
The definite article (the an, am, a’, na word meaning the) is explained in the tips and notes for skills:
- Food 2 – the masculine definite article,
- Animals – the feminine definite article,
- Travel – the plural definite article.
There is more to the article – it behaves differently in genitive and dative cases, that’s not yet covered in Duolingo – you can read more about it on Akerbeltz wiki in the Masculine nouns and Feminine nouns articles.
As for the tips and notes, they are available on the web browser version of Duolingo at https://duolingo.com and on the https://duome.eu/tips/en/gd website. They might not be available in the mobile Duolingo app, so if you use Duo on mobile, you might want to open your web browser for reading.