The ultimate total number of ZX Spectrum computers produced

[Alone Coder]

I'm sorry for my mistake.

2) Amstrad CPC and PCW - more than 11 millions;
3) Tandy TRS-80 - about 10 millions;

This is a misinterpretation of the statement "Tandy had 11 million customers that might buy a microcomputer". It was pricey and couldn't sell much more than Commodore VIC-20, despite the long lifespan. It only has some 100 games.
The official numbers for Amstrad PCW don't match its versions count and the usage. It looks very rare.

[Alone Coder]

In any case, it seems that over 50% of ZX Spectrum users live in non-English-speaking countries. Most of them use European languages such as Spanish and Portuguese.
So, the new question is... are there games in Interlingua?

[NEO SPECTRUMAN]

Interlingua?

Interlingua not needed

[Polrai]

Yes I think the Tandy TRS-80 sold about 250000 units. The Amstrad figures are Amstrad official numbers, you can trust them or not...

[+3code]

Interlingua no, but we have one MIA title to learn esperanto ( https://spectrumcomputing.co.uk/entry/1 ... _Esperanto ), and I've found this other: https://wowroms.com/robots.txt/roms/zx- ... 42735.html

I think is an esperanto tutorial in slovak, serbian or something so.

[Polrai]

It's Croatian.

[Alone Coder]

Interlingua no, but we have one MIA title to learn esperanto

The point of Interlingua is that you don't need to learn it to read it
As I suppose, the game words (uncovered in dictionaries) are:

left - a leve
right - a dextre
up - al alto
down - al basso
fire - discargar
pause - pausar

start game - initiar le joco
keyboard - claviero
joystick - barra de commando
define keys - definir le claves

level/world/zone - nivello/mundo/zona
score - punctos
lives - vitas
game over - fin de joco
congratulations - congratulation

As you see, all of them are international words

[Alone Coder]

One more machine: Арго ФВ-6511 (made in Ukraine, 1991) was both ZX Spectrum compatible and Radio-86RK compatible.