ha a nagyanyámnak kereke volna, gurulna

• Instead of “a nagyanyámnak” (“[to] my grandmother”), the following variants also occur: nagyanyámnak (without article), (a) nagymamámnak, (az) öreganyámnak (also “[to] my grandmother”) as well as (a) nénikémnek, (a) nagynénikémnek (“[to] my aunt”). A nagypapámnak (“[to] my grandfather”) occurs with talicska (“wheelbarrow”).
• Before “kereke volna” (“had wheels”), the numerals négy (“4”) or hat (“6”) can occur.
• After the comma, akkor (“then”) can occur without any change in meaning.
• Instead of “gurulna”, ő volna/lenne/lehetne a villamos/trolibusz/gőzmozdony or ő volna/lenne/lehetne az omnibusz (“she would/could be a tram/trolley-bus/steam-locomotive/omnibus”) are also possible, as well as omnibusznak neveznék (“she would be called an omnibus”).

ha (“if”) + a (“the”) + nagyanya (“grandmother”) +‎ -m (“my”, first-person singular possessive suffix) +‎ -nak (“to”, dative suffix) + kerék (“wheel”) +‎ -e (“her”, third-person singular possessive suffix) + volna (“there would be”) + gurul (“roll”) +‎ -na (“would”, conditional suffix).

Literally: "If my grandmother had a wheel [or: wheels], she would roll."

• IPA^(key): [ˈhɒɒ ˈnɒɟɒɲaːmnɒk ˈkɛrɛkɛvolnɒ ˈɡurulnɒ]

ha a nagyanyámnak kereke volna, gurulna

1. (idiomatic) if my aunt had balls, she'd be my uncle (there is no point in discussing unreal and/or impossible scenarios)