My son likes to play with other kids, but he's shy and will usually join someone else in their game and not initiate. That is fine with us, the problem is that English is his second language, and he seems to be afraid of opening his mouth and speaking it. He's much more relaxed when speaking his mother tongue, although we know he understands everything in both. We try to encourage him to have play dates with English speaking friends, but he chooses older kids (multi age group) who don't always want to meet him outside school. We simply can't convince him to name other friends, even though he's very jealous of his older sister's play dates.
I think it would help if the kid has some toys or activities he was really proud to show off to his peers. A really cool gun or some sort of a trampoline or a swing rope.
For my kids, who are also multilingual, it helped having a Wii. Other kids that age didn't have one (actually the Wii was ours), so it was pretty cool to come and play with them.
After a little while, everybody is happy to move on and play outside or with other toys.
From what you say, it looks like your kid is still learning english. Be patient, it takes a long time until they feel comfortable.
We simply can't convince him to name other friends
At that age it's common for them to just play with whoever is doing what they are doing at playground/kindy. I suggest you quietly check in with their teacher/carer and ask them who they think your child gets on well with. Also make friends with other parents in your childs class, generally parents that you get on well with who have nice kids will make good play dates.
Make your garden into an adventure space, trampoline, sandpit, logs to step across, even an old boat all make for good adventure space. Get kids outside exploring together and they'll sort it out themselves.