Titus Livius, Ab Urbe Condita XL, 57
'the Scordisci will let the Bastarnae pass without difficulty; their languages and customs are, after all, very similar, and the Scordisi may well join up with the Bastarnae, seeing that the latter are going in search of spoils to a very wealthy people' (quoted from Shchukin).
Latin: 'nec enim aut lingua aut moribus [aequales] abhorrere',
http://www.thelatinlibrary.com/livy/liv.40.shtml#57
"not dissimilar" is probably better.
Torsten