Have you noticed that in words like shika (“deer” ) and hiku (“to pull” ), the “i” sound is almost inaudible?  This often happens also at the ends of the grammatical endings desu and masu, which are pronounced [dess] and [mahs], respectively. We call this devoicing “i” and “u”. That means that they become almost “whispered.” This happens when these vowels come between two of the voiceless consonants: p, t, k, s, or h.
Also, you will notice that in Japanese, there are some sound syllable sounds that don’t exist.

For example:
“si” doesn’t exist, but is replaced by “shi”.
“ti” becomes “chi” and “tu  which becomes “tsu”
“hu” doesn’t exist, “fu” is used. However, the “fu” sound is a lot lighter than in English.
(To make the sound, blow air between the lips, and not between the lips and teeth. Imagine this sound as being a combination of both “h” and “f.” )

“yi” and “ye” sounds don’t exist  in modern Japanese.There is also no “L” block of syllables in Japanese. Instead, you will find that in many words borrowed from English, in Japanese pronunciation and katakana writing, it has become replaced by a very light “r” sound. To make this “r” sound, lightly tap the roof of your mouth with your tongue, and try to think of it like a light “d” sound, as in saying the name “Eddy” quickly.
It may take some getting used to, but remember that the “r” sound is the closest sound there is in the Japanese pronunciation group. What borrowed words can you think of that have been apparently changed when pronounced in a Japanese way?