Maryam Verse 3

when he cried out to his Lord privately,

When he called upon his Lord in private.

when he called upon his Lord secretly

when he called to his Lord secretly, saying,

Recall what time he cried unto his Lord with a cry secret.

Behold! he cried to his Lord in secret,

when he cried to his Lord in secret.

When he called to his Lord inwardly,

When he softly prayed to his Lord.

when he called out to his Lord with a secret cry.

When he invoked his Lord with a call in secret,

When he called upon his God, crying aloud (in humble supplication).

When he called/cried (to) his Lord a hidden/secret call/cry.

When he softly prayed to his Lord.

A mention of your Lord´s mercy to His servant Zachariah,

When he called out his Lord (Allah) a call in secret,

A mention of the mercy of thy Lord to His servant Zacharias --

When he called upon his Lord in a low voice,

When he cried unto his Lord a cry in secret,

When he quietly called his Lord

when he called upon his Lord in secret,

When he called his Lord [with] a call in secret.

when he called upon his Lord in low tones, saying,

When he called on his Lord, a call in seclusion.

when (idh is semantically connected to rahma, `mercy') he called out to his Lord a call, entailing a supplication, in secret, in the middle of the night, because this [time of the night] invites a faster response [to one's supplication].

When he called his Lord (with) a call in secret.

He only made his supplication secretly because it is more beloved to Allah.

This is similar to what Qatadah said concerning this Ayah,
إِذْ نَادَى رَبَّهُ نِدَاء خَفِيًّا
(When he called out his Lord (with) a call in secret),

"Verily, Allah knows the pious heart and he hears the hidden voice.