We get too many cards round work these days and I've been tempted to start signing them with gibberish. I mentioned this to my sister-in-law when we were talking about signing her bright red leg-cast (achilles tendon snap, if you hadn't heard). She says it's stupid, but I think she thought it was a cleverer idea than she'd ever admit. (She doesn't like to humour me as she knows nothing good comes of it...)
Here are a few possible gibberish phrases. Feel free to use them.
Ar Fflarffan Boingo (pretend it's Welsh)
Grond Toglwogl (ersatz Norwegian - or possibly Greenlandic)
Hin Qin Tai Che Roh (could be from any Asian country)
Lapsis Anagooksis (faux Greek - you could additionally claim it's a Cypriot dialect)
NB - to get away with using nonsense greetings is just be confident if anyone asks you what it is. "Well it' s the customary greeting of the Lammu tribe in Vietnam. I just thought it would be fun."
After all, who's gonna know?