It's simple, take an English phrase, and switch one sound back or forward one place of articulation, change it's voice, or change it's mode, (for vowels just move it up, down, left, or right one) and see what you get! Come up with a grapheme which will represent this sound unless it already has an English one. Then the next player can repeat!
Just post an IPA transcription of the text the line below it. It will help you. So will the images above.
/dʒʌst poʊst æn aɪ pi eɪ trænskrɪpʃən əv ðə tɛkst ðə laɪn bilow ɪt ɪt wɪl hɛlp juː soʊ wɪl ðə ɪmədʒɛz əbʌv/^ that should be pretty close, at least close enough for the purposes of this, it will quickly get messy