I was confused by 'Léim' having connections to Jump and Read too. The difference is: 'Léigh' is 'To Read', the infinitve, and in conjucated as 'Léim - I read, Léann tu, Léann sé' so on.
Now 'Léim' is 'To jump' The infinitve, but it comjugated as 'Léim mé' I jump, Léim tu You jump.
Basically Léigh is more irregular than Léim, but share the samw sound.
Hope this helps.