<p>In French, the <strong>circumflex (^)</strong> on a vowel usually indicates the historical presence of a letter, most commonly <span style="font-style: italic;">s</span> (rarely <span style="font-style: italic;">e</span>). For example, <span style="font-style: italic;">connaître</span> derives from the Old French word <span style="font-style: italic;">conoistre</span>. </p>
<p>Since the i-circumflex indicates a missing <span style="font-style: italic;">s</span> after the <span style="font-style: italic;">i</span> in verbs that end in <span style="font-style: italic;">-aître</span>, <span style="font-style: italic;">-oître</span>, the circumflex isn't used in verb forms where an <span style="font-style: italic;">s</span> comes after the <span style="font-style: italic;">i</span> (<span style="font-style: italic;">je connais</span>), only when a <span style="font-style: italic;">t</span> comes after it (<span style="font-style: italic;">il connaît</span>).</p>
<p><strong>Exception:</strong> <span style="font-style: italic;">croître</span> (the i-circumflex is used even before an <span style="font-style: italic;">s</span> to distinguish it from the forms of <span style="font-style: italic;">croire</span>).</p>
French conjugation explanation