Noise control and acoustics

The seventh entry is a transmissão marginal, and the adjective inside it is a trap for an English reader. « Marginal » in English means slight, borderline, barely worth counting: a marginal improvement, a marginal gain, a marginal case. Carry that reading across and the term says the opposite of what it names. A transmissão marginal is the sound that travels round a partition instead of through it, by way of the floor, the ceiling and the walls that meet it. It is the reason a wall tested in a laboratory performs worse once it has been built into a flat, and on a poor job it settles the result on its own. Nothing about it is negligible. English names it after the side of an army rather than after the edge of a page: « flanking transmission », and the routes it follows are « flanking paths ». The Portuguese adjective is looking at a margem, the border of the building element; English is looking at the flank of the thing being got round. Write « marginal transmission » in a report and a reader will hear « negligible » and agree with the wrong sentence.