Ecstacy features the same EMS vocoder they used on The Beach. Apparently it was very unreliable - a lot of their gear was dodgy then - and the only times it worked long enough to record to tape was when Ecstacy and The Beach were being recorded. It then stopped working and, even though they spent loads on getting it repaired, it never worked again!
There has long been a rumour that the whole of Blue Monday was originally vocodered and the "when your heart goes cold" line used on The Beach is a snippit from it.
It's not surprising that vocoders make it hard to understand exactly what's being said: Yellow Magic Orchestra often used a Roland one and, coupled with Ryuichi Sakamoto's broken English with a strong Tokyo accent, it's quite difficult to understand what he's on about! Behind The Mask is a real classic but you try and listen to what he's singing!