Even when making a temporary sign, the presentation is extremely important. As mentioned above, the more languages you have, the more space you need. Therefore 4-language signs should be as short and concise as possible. Consider these examples.
Figure. Bad example 1 (toilet)
Figure. Bad example 2 (too wordy, and simply pasted next to sign)
The first figure shows how too much signage can be defeating to the purpose. Therefore, it is important to pick a location that will get the message across clearly and unfailingly. The second figure is an example of trying to put too much wording on the same sign as the original. The result is a barely legible mish-mash of non-information.
Figure. Good example 1 (toilet with QR code)
Figure. Good example 2 (colored caution sign)
On the other hand, these signs are clear, legible and unwordy. The first example has just one or two words for each translation, which is placed clearly above the original sign. Moreover, any misunderstandings can be cleared up by accessing the QR code on the side if necessary. The second example, although not perfectly translated, makes use of 4 languages, an international icon (the caution triangle), an illustration, and a highly appropriate color scheme of black and yellow (internationally meaning caution) and red (internationally meaning danger).