The card Atinlay Igpay has the ability oubleday ikestray. Is this functionally different from double strike?
Nop, it's the same.
Keep in mind, Atinlay Igpay is a card from the unhinged set. Meaning you can't normally play it except for casual play (and then usually you have to agree on it specifically).
The card is actually called Latin Pig in Pig-latin rules:
Juvenile "code" language created by the rearrangement of sounds in a word such that the first sound is moved to the end and "ay" is added. In the case of a vowel as the first sound, "ay" is simply added, with an hyphen if necessary.
This is also how Double Strike turns into Oubleday Ikestray.
oNay, oubledayyay ikestrayyay isyay otnay onlyyay unctionallyfay identicalyay otay oubleDay ikeStray, ityay actuallyyay isyay oubleDay ikeStray
atThay isyay ecausebay allyay exttay onyay ethay ardcay "igpayyay atinlayyay" isyay enderedray inyay igPay atinLay, ichwhay ashay ellway-efinedday ulesray orfay itsyay eationcray. ereforeThay, otay akemay ethay ardcay eadableray, youyay avehay otay irstfay onvertcay ityay ackbay otay egularray Englishyay
Just as "Doppelschlag", "Doppio attacco", "Golpe duplo", and many others; "Oubleday ikestray" is just a regular "Double Strike" on a non-english card.