Using a mixture of English and a made-up language?

Wondered how well this would work or if anyone would be put off by it. To put a long story short, the creatures I have created were forcibly made sentient by humans, who then partially-taught them English before the creatures escaped the space station they were being held captive in and started their own society on the planet they were orbiting.

The creatures are called Sindryl and mostly speak in English (as it is the only language they've ever known). However, for alien items not known to humans, words which they were never taught before they escaped, and newly-created items, they tend to make up words. As the world is inspired by Middle-eastern architecture and influences, I decided to make these made-up words more foreign-sounding. Things like 'fakisas' (sound a lot like fajitas), which are a sort of dessert food there, the use of the phrase 'tche tche tche!' (Pronounced 'ch-eh') when a Sindryl is in pain, and 'Isaiyo', meaning 'gangs'.

I have more words to add to this, but the whole point is: is this an understandable language behavior (to make up words when no word is available), and is it offensive in any way to other languages? I wouldn't think it is but I thought I'd check just to be sure.

Many thanks! - Rin

This seems like completely understandable behavior to me (as in, I can see why they would do it, and it makes sense) and as far as I know, it isn't offensive to other languages - not that I'm in any way an expert on the subject.

Hope this helps! - Kim

I agree with @KHope1602. I'm not a linguist, but my understanding is that's how language is created: there is a hole, and a new word is created or borrowed to fill in the gap, or known words evolve over time.

You might be interested in researching how new words are created in Chinese. They take known words and combine them to create a new word with a new meaning. For example, 电话 dian hua is telephone. 电 dian means "electricity" and 话 hua means "words" or "to talk (about)". Computer is 计算机 ji suan ji. 计算 ji suan is "calculate" and 机 ji is "machine".

Some words are also onomatopoeia – naming an object or sound after the sound itself. Like a cuckoo clock, or a child calling a cat "meow".

Not to mention that some words are shorted versions of others (like "slang" is slang for "short language").

You have a lot of options for coming up with new words, and what you're describing is a totally natural occurrence!

Not at all. It's generally accepting that the way languages are formed is BS. That kind of thing isn't at all out of place.
I assume they use the Latin alphabet?
For uncommon words they wouldn't likely have whole new words, but mostly have hybrid words. Like every fruit-like thing being, "Bluefruit" (blueberry) "Greenfruit" (Avocado) "Grainyfruit" (Pear) "Bloodfruit (Pomegranate)
There can, of course be exceptions. The language would likely stray from English even more as it went on. So, several thousand years later, we probably wouldn't be able to understand it.

Read Bill Bryson's 'The Mother Tongue: English and How it Got That Way'