conversation at Narita airport

Because all staff working at the airport can speak English, you need not to speak Japanese at the airport.
So you should better try using Japanese as a kind of a practice.

At Limousine bus counter;

You: Shinjuku iki no basu ni noritai no desuga.
Clerk: Tsugi no basu wa juuji juugofunn desu.
Y: Sono basu de onegaishimasu.
C:San zen en ni narimasu.

Shinjuku : (name of town)
iki : bound for (noun of "iku"(go))
no: (connecting word between noun and noun)
desuga : (literaly " ...is. but ".) I mean
tsugi : next
basu : bus
juu : (number) ten
ji : hour
juugo : (number) fifteen
fun : minute
sono : that , it
onegaishimasu: please
san : (number) three
zen : =sen , thousand
en : yen
ni narimasu: (literaly means " become...". ) is

Shinjuku iki no basu ni noritai no desuga: Shinjuku, bound for, bus, on, get on , want ,I mean: I want to get on a bus bound for Shinjuku.
Tsugi no basu wa juuji juugo fun desu.: next, bus, ten, hour, fifteen, minute : Next bus is 10:15.
Sono basu de onegaishimasu.: That, bus, please : I get on that bus.
San zen en desu.: three, thousand, yen, is.: 3,000yen.