user19877: I have heard "fianchetto" for four decades now, and I have always pronounced it "fēənˈCHetō", but I have heard many people also pronounce it "fēənˈketō".
It is of Italian origin, so I am wondering if there are any Italians out there, especially natives, or anyone really, who can tell me what is the true, and proper, pronunciation.

user20721: When in Rome speak Roman.  
They may say fi an Ket oh  in Italy,  but the rest of the world says fi an CHet oh.  
Words change meanings and pronounciations over time and the majority usage eventually wins out.  
I always have heard fi an Chet oh and that is how I say it.

user15647: Fianchetto is commonly pronounced in English as /fiænˈtʃɛtoʊ/ (soft ch as in "cherry") but the original Italian word is pronounced /fjaŋˈketto/ (hard ch as in "chaos"). Note the word is cognate to English flank.
It is common for terms borrowed from other languages to take on 'erroneous' pronunciations if the inherited orthography is ambiguous e.g.

cherub (Latin: /k/; English /tʃ/)
pistachio (Italian: /k/; English /tʃ/)
bruschetta (Italian: /sk/; English: /ʃ/)


user-1: In Italian, c is pronounced like English "ch" or "tsh" before "i" and "e" and like "k" (unaspired) before "a", "o", and "u".  If you want it as "k" before "i" and "e", you add an "h" in between, if you want it as "tsh" before "a" (and probably the other dark vowels as well), you add an "i" in between that is not (or hardly) being pronounced.
Similar with "g".
So ciabatta is "tshah-baht-tah", giotto is "jot-to", Giuseppe is "ju-sep-pe", fianchetto is "fee-ahn-ket-to".

user4418: According to Wikipedia:

In chess, the fianchetto (/ˌfiænˈtʃɛtoʊ/; Italian:
  [fjaŋˈketto] "little flank") is a pattern of development ...

Hence English speakers pronounce the "ch" as in "chess" and Italian speakers as in "kettle".
Which suggests that there is no "true, and proper, pronunciation".

user20795: While I'm not sure exactly how "fēənˈketō" would be pronounced (I'm not a native English speaker), that's more correct as to the pronunciation of the "ch" (following the Italian pronunciation).
The pronunciation written in English would be something like fee-ahn-keh-toh, with the accent on the third syllable (keh).
I just found this website in which there are actual recordings of italian (I hope) people pronouncing it. It sounds pretty good to me.

19877: <p>I have heard "fianchetto" for four decades now, and I have always pronounced it "fēənˈCHetō", but I have heard many people also pronounce it "fēənˈketō".</p>

<p>It is of Italian origin, so I am wondering if there are any Italians out there, especially natives, or anyone really, who can tell me what is the true, and proper, pronunciation.</p>
 20721: <p>When in Rome speak Roman.  </p>

<p>They may say fi an Ket oh  in Italy,  but the rest of the world says fi an CHet oh.  </p>

<p>Words change meanings and pronounciations over time and the majority usage eventually wins out.  </p>

<p>I always have heard fi an Chet oh and that is how I say it.</p>
 15647: <p><em>Fianchetto</em> is commonly pronounced in English as /fiænˈ<strong>tʃ</strong>ɛtoʊ/ (soft <em>ch</em> as in &quot;cherry&quot;) but the original Italian word is pronounced /fjaŋˈ<strong>k</strong>etto/ (hard <em>ch</em> as in &quot;chaos&quot;). Note the word is cognate to English <em>flan<strong>k</strong></em>.</p>
<p>It is common for terms borrowed from other languages to take on 'erroneous' pronunciations if the inherited orthography is ambiguous e.g.</p>
<ul>
<li><em>cherub</em> (Latin: /k/; English /tʃ/)</li>
<li><em>pistachio</em> (Italian: /k/; English /tʃ/)</li>
<li><em>bruschetta</em> (Italian: /sk/; English: /ʃ/)</li>
</ul>
 -1: <p>In Italian, c is pronounced like English "ch" or "tsh" before "i" and "e" and like "k" (unaspired) before "a", "o", and "u".  If you want it as "k" before "i" and "e", you add an "h" in between, if you want it as "tsh" before "a" (and probably the other dark vowels as well), you add an "i" in between that is not (or hardly) being pronounced.</p>

<p>Similar with "g".</p>

<p>So ciabatta is "tshah-baht-tah", giotto is "jot-to", Giuseppe is "ju-sep-pe", fianchetto is "fee-ahn-ket-to".</p>
 4418: <p>According to <a href="https://en.wikipedia.org/wiki/Fianchetto" rel="noreferrer">Wikipedia</a>:</p>

<blockquote>
  <p>In chess, the fianchetto (/ˌ<strong>fiænˈtʃɛtoʊ</strong>/; <strong>Italian:
  [fjaŋˈketto]</strong> "little flank") is a pattern of development ...</p>
</blockquote>

<p>Hence English speakers pronounce the "ch" as in "chess" and Italian speakers as in "kettle".</p>

<p>Which suggests that there is no "true, and proper, pronunciation".</p>
 20795: <p>While I'm not sure exactly how "fēənˈketō" would be pronounced (I'm not a native English speaker), that's more correct as to the pronunciation of the "ch" (following the Italian pronunciation).</p>

<p>The pronunciation written in English would be something like <code>fee-ahn-keh-toh</code>, with the accent on the third syllable (<code>keh</code>).</p>

<p>I just found this <a href="https://forvo.com/word/fianchetto/" rel="noreferrer">website</a> in which there are actual recordings of italian (I hope) people pronouncing it. It sounds pretty good to me.</p>
