Here in the USA, I have been paying more attention to the USPS International Mailing Manual, and I have been experiencing a perception of noticeably faster mailing speeds.
Section 122.1d specifies that an address translation must be provided, or “If the English translation is not known, the foreign language words must appear in roman characters (either printed or script).”
Section 244.2a specifies that “First-Class Mail International postcards, letters, and large envelopes (flats) must be marked “AIRMAIL/PAR AVION” or have PS Label 19-A, Par Avion Airmail, or PS Label 19-B, Par Avion Airmail, affixed to the address side of the mailpiece.” (Note: PS Labels 19-A & 19-B are no longer provided by USPS. Is PAR AVION required? The Step-by-Step instructions say that you can write it, and then shows an example with AIR MAIL in English only. So I think not.)
I have acquired a rubber stamp that prints AIR MAIL in red ink with letters about 1/2 inch (1.27cm) high.
Therefore, I have been:
Handwriting addresses using roman characters.
No address labels or stickers (Here’s why.)
Affix the red AIR MAIL rubber stamp impression.
My perception is that cards have been whizzing to their destinations at least a week faster on average if not more. Admittedly, due to current restrictions, most of these cards are to eastern and western Europe. But looking at my sent history for Europe only, they still seem faster.
It seems that getting the cards out of the USA is an important component of delivery speed, even if the receiving postal service has to do some translation. I’ll look forward to expanding my experiment when restrictions are lifted and more cards go to countries that use non-roman alphabets. I recognize that post-COVID improvements in either the sending or receiving country could also have an effect.