Hindi and English have several similar yet distinct phonemes.

1. /v/ and /w/ - The English /w/ is bi-labial (both lips touching) similar to Hindi व. The English /v/, however, is labio-dental (upper teeth touching lower lips), a sound distinct for the English speaker but indistinguishable from /w/ for Hindi speakers.
2. /ph/ and /f/ - English uses labio-dental /f/, Hindi, however, uses bi-labial /ph/फ. Fun fact: These two sounds were distinct for ancient Greeks. But not to English speakers. So, Telephone and Telefone would have the same pronunciation, that is, /f/ in English.
3. /ɹ/ and /r/र - The English r ( /ɹ/) is retroflex (tongue curling backward like ट). In fact, that’s the only retroflex sound in English, Hindi /r/, however, is generated at the alveolar ridge (the ridge right behind your upper teeth). Fun fact: The Sanskrit ऋ is pronounced /ɹ/
4. English /t/ vs Hindi /t/त - The English T sound is unique in many ways. It does not exist even in other major European languages like Spanish, French, and German. Both Hindi’s त and English T are made at the alveolar ridge. The Hindi/Spanish/French/German /t/ is made with the tip of the tongue while the English /t/ is made with the blade of the tongue giving it a thicker sound.
5. /θ/ (th) vs tʰ/थ - The Hindi थ is dental in nature, the sound is made by touching the tip of the tongue with the back of the upper teeth. While the English /θ/th sound is interdental, for example, in thinking or thin. This sound is made by putting the tongue tip between the upper and lower teeth while simultaneously touching both.
6. /ð/ vs /d/द - Similar to थ, the Hindi द is dental in nature. The English /ð/ is inter-dental in nature. For example, in “this” or “father”, the th sound is produced by the tongue hanging between the middle teeth. The English /d/ is non-retroflex and is pronounced in the same spot as the Hindi द. So, the transliteration of London as “लंदन” isn’t too far from being correct!
7. /ʒ/ vs /dʒʱ/झ - Consider the second sound in “vision” or the third sound in “decision”. It gets incorrectly approximated as /z/ज़ or /s/स. /ʒ/, however, is made by touching the tongue to the ceiling of the mouth and creating friction. It might be easier for Hindi speakers to imagine this as a fricative version of झ.