Several translations of Sutra II 50:
Alice Bailey
Right control of prana (or the life currents) is external, internal or motionless; it is subject to place, time and number and is also protracted or brief.
BonGiovanni
It may be external, internal, or midway, regulated by time, place, or number, and of brief or long duration.
Kofi Bufia
The different types of this control are?to surrender it up, to draw it in, or to hold it completely still, for different times, and in different stages and quantities. In this way it becomes long and subtle.
Mark O. Garrison
The modifications of the life-breath are either external, internal or stationary. They are to be regulated by space, time and number and are either long or short.
Hariharananda Aranya
That (Pranayama) Has External Operation (Vashya-Vrtti), Internal Operation (Abhyantara-Vrtti) And Supression (Stambha-Vrtti). These, Again, When Observed According To Space, Time, And Number Become Long And Subtle.
Chip Hartranft
As the movement patterns of each breath - inhalation, exhalation, lull - are observed as to duration, number, and area of focus, breath becomes spacious and subtle.
Vyasa Houston
(Pranayama has) external, internal or suspended modifications (which become) long and subtle, when observed by means of location (of breaths motion in the body), time (length of inhalation, exhalation and intervening spaces), and number.
B.K.S. Iyengar
Pranayama has three movements: prolonged and fine inhalation, exhalation and retention; all regulated with precision according to duration and place.
Charles Johnston
The life-current is either outward, or inward, or balanced; it is regulated according to place, time, number; it is prolonged and subtle.
Bart Marshall
Intentional breathing controls the three phases of breath?exhalation, inhalation, and hiatus. Breathing can be regulated by controlling the spacing, depth, number, and duration of breaths.
Chester Messenger
Breath control has three phases: prolonged and fine inhalation, exhalation and retention; all regulated with precision according to duration and place.
Barbara Miller
The modification of breath in exhalation, inhalation, and retention is perceptible as deep and shallow breathing is regulated by where the breath is held, for how long, and for how many cycles.
Swami Jnaneshvara Bharati
That pranayama has three aspects of external or outward flow (exhalation), internal or inward flow (inhalation), and the third, which is the absence of both during the transition between them, and is known as fixedness, retention, or suspension. These are regulated by place, time, and number, with breath becoming slow and subtle.
Swami Prabhavananda
The breath may be stopped externally, or internally, or checked in mid-motion, and regulated according to place, time and a fixed number of moments, so that the stoppage is either protracted or brief.
Swami Satchidananda
The modifications of the life-breath are either external, internal or stationary. They are to be regulated by space, time and number and are either long or short.
Swami Vivekananda
Its modifications are either external or internal, or motionless, regulated by place, time, and number, either long or short.
I.K. Taimni
(It is in) external, internal or suppressed modifcation; is regulated by place, time and number, (and becomes progressively) prolonged and subtle.