hi @cryptogee. I am a native speaker. You speak quite well and it is understandable. You can try this trick. The end of the words you can try to drag it a bit longer. But if you learn the four intonation for each sound, you will get very accurate variation in tone that will make the difference in almost similar sounding words. Example : Mother 妈 and horse 馬 they both uses the same pronunciation (ma) but with different tone.