Using the Pig Latin translator
Type English on the left, copy Pig Latin from the right.
This one only runs forwards, so the swap button is switched off and the page says why below. Capitals and punctuation stay where they are: "Hello, world!" keeps its comma and its exclamation mark.
The rules
A word starting with a vowel takes "way" on the end, so apple becomes appleway. A word starting with consonants sends the whole opening cluster to the back and adds "ay": hello becomes ellohay, and smile becomes ilesmay, because sm travels together.
Y is the awkward one. Starting a word it counts as a consonant, so yellow becomes ellowyay. Anywhere else it counts as the vowel, and my becomes ymay.
Why it only goes one way
Pig Latin throws information away. Ellohay could have been hello. Ouryay could have been your, or oury. Once the consonants have moved and "ay" is stuck on the end, nothing records where the split was, so a reliable reverse doesn't exist.
Converters here that run both ways say so. The ones that can't explain themselves rather than offering a button that quietly guesses.
The words that escaped
It's a children's game, written down as "Hog Latin" in the 19th century and played long before anyone bothered to record the rules.
What lifts it above the other playground codes is that some of its output got out. "Ixnay" is Pig Latin for nix and "amscray" is scram, and both are in dictionaries now, used by people who never played the game.
Related conversions
Pig Latin rearranges the sounds inside words. Upside down text leaves the words alone and changes their shapes, and runes change the alphabet while the English underneath stays put.
For something a reader can't work out on sight, ROT13 and Atbash are the gentlest ciphers here.
Questions
Is Pig Latin a real language?
No. It's a word game played on English, most often by children, and it's been around in some form since at least the 19th century.
What happens to punctuation?
It stays where it is. Only the letters move.
Why do translators disagree?
The rules are folk rules. The vowel ending is sometimes "way" and sometimes "yay", and people split consonant clusters differently.
Can anything translate Pig Latin back?
Not reliably, here or anywhere. A person reading in context does better than a converter, because context is the only thing that settles the ambiguity.
Is there a reverse Pig Latin translator?
Not a reliable one, here or anywhere. Ellohay could have been hello, and ouryay could have been your or oury, so any reverse translator is guessing. Reading it yourself in context beats a tool.