Breaking down "atyadhik" (excessive), Zoya thinks its two parts are "ati" and "adhik", and assumes…
Breaking down "atyadhik" (excessive), Zoya thinks its two parts are "ati" and "adhik", and assumes two vowels here will combine into a third vowel, like "Suresh". Her friend says a vowel here turns into a consonant itself. Who is right?
Who do you think is right? Pick one.
The answer: Her friend is right, "i" itself turns into "y" — ati + adhik = atyadhik
Why
Zoya has correctly identified the two parts, but is assuming every vowel-meeting-vowel situation follows the same गुण संधि pattern seen in 'सुरेश' — a reasonable but incomplete generalisation, since Hindi-Sanskrit sandhi has more than one rule for vowels meeting vowels. 'अति' ends in 'इ', and 'अधिक' begins with 'अ'; here, rather than merging into a new vowel, the 'इ' itself TURNS INTO the consonant 'य्' — giving 'अत्+य्+अधिक' = 'अत्यधिक'. This is यण संधि (yan sandhi), the same rule family already seen with 'सु'+'आगत'='स्वागत' (where 'उ' turned into 'व्'). Test it: 'इति'+'आदि' becomes 'इत्यादि' the same way — 'इ' turning into 'य्', not merging into a shared vowel. Her friend is right: in 'अति'+'अधिक', the 'इ' turns into the consonant 'य्' — this is यण संधि, a different mechanism from the vowel-merging seen in 'सुरेश'.
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