Did you check this:

'apples' => '{0} There are none|[1,19] There are some|[20,Inf] There are many',

from the documentation? (http://laravel.com/docs/localization)

I have but I was trying to use the first example they have in the documentation:

'apples' => 'There is one apple|There are many apples',
echo Lang::choice('apples', 10);

I have pretty much exactly the same thing as the first example in the documentation:

'customer' => 'customer|customers';
$num_customers = count($customer_array);
echo Lang::choice('customer', $num_customers);

And it works fine as long as $num_customers < 20. As soon as it becomes larger, that's when the error shows up without changing anything other than that $num_customers.

I'm trying to keep it simpler than using :

'customer' => '[0,1] customer|[2,Inf] customers',