Five is not a number

We've been teaching Henry to count for some time now and since he was one he's been able to count to six but he will never ever say five or any other number which includes five. Why this is we don't know. We practice counting when we walk down the stairs, we count the cars in the car part, we count the number of mosquitoes buzzing around our heads, we count the leaves on the trees, we count the number of sultanas mashed into the carpet, we count number of times he asks me to read the truck book each day and even though we deliberately say FIVE really loudly each time we get to it he won't ever repeat it.

We took a video of him just the other night counting the placemats he had placed on the floor; "one, two, free, four, six, leven, twelve, fourteen, sixteen...(clap, clap, clap), yay that was great everybody". No five, we tried to trick him into it, we tried to bribe him to say five but he just won't say it. The chinese believe that four is an unlucky number and won't use any combination of it in anything. Perhaps Henry believes the same thing about the number five and knows something we don't.